Filler cap for fuel tank and valve body device for fuel tank

ABSTRACT

Immediately after attaching a filler cap to a fill opening, a spring raises a valve body and the rise/fall member, so that a laterally outer circumference of a valve body point contacts with plural convex portions of a second side wall, thereby closing the valve portion. In such a state, coming and going of a fluid between a first space S 1  and an opening S 3  is not allowed. When a pressure in the fuel tank reaches 5 kPa, the fluid rise a first air passage formed in spaces between respective convex portions on the second side wall, passing the valve portion. Rising fluid lowers the valve body to allow discharging an excessive pressure to the exterior of the fuel tank.

FIELD OF THE INVENTION

The present invention relates to a filler cap for a fuel tank providedin automobile etc. and opening/closing a fuel filler port, and a valvebody device for the fuel tank provided in the automobile etc.

BACKGROUND ART

Conventionally, the filler cap for the fuel tank of aninternal-combustion engine is provided in the automobile that isrequired to draw an atmosphere therein by the volume corresponding to afuel consumed in the fuel tank. For such drawing, an air passage fordrawing the atmosphere is provided in the filler cap.

For this reason, when the fuel tank provided in the automobile etc.inclines at more than a predetermined angle, there was a danger of thefuel leaking from the air passage and catching fire.

In view of the above, the applicant has proposed a filler cap (refer topatent documents 1 and 2). When the fuel tank inclines at thepredetermined angle, this filler cap can securely suppress theinconvenience that the fuel in the fuel tank flows out of the airpassage provided in a main body of the filler cap.

In the filler cap disclosed in the above patent documents 1 and 2, withthe fuel tank inclined at the predetermined angle and the fuel flowinginto a cylinder main body, when a float constituting a valve mechanismportion provided in the air passage floats externally, a sphere alsoconstituting the valve mechanism portion is pressed on areduced-diameter portion of the cylinder main body by the float, therebyclosing the air passage. However, in the state where the above fuel tankis not inclined, harmful gas evaporated from the fuel may be dischargedto an exterior of the fuel tank from a gap existed between a piston andan inner surface of the cylinder main body. This harmful gas has aproblem of causing an environmental pollution that leads to difficultyin a consumption improvement of the fuel.

PRIOR ART DOCUMENT

[Patent document 1] Japanese Patent No. 5,030,152[Patent documents 2] U.S. Pat. No. 7,823,611

SUMMARY OF THE INVENTION

In view of the above situation, the present invention has a first objectto provide a filler cap for a fuel tank and a valve body device for afuel tank that does not discharge the harmful gas evaporated or the fuelto an exterior of the fuel tank, until pressure in the fuel tank reachesa predetermined value, thereby preventing an environmental pollution andalso improving a fuel consumption. The present invention has a secondobject to provide a filler cap for a fuel tank and a valve body devicefor a fuel tank that does not discharge the fuel to the exterior of thefuel tank, when the fuel flows into from the fuel tank due to theinclination of the fuel tank at a predetermined angle, therebypreventing the environmental pollution and also improving the fuelconsumption.

In a first aspect, the first invention provides a filler cap for a fueltank attached to the fuel tank, the filler cap comprising a cap mainbody including an outer cap and an inner cap, the filler cap having anair passage for communicating an interior and an exterior of the fueltank, and a valve mechanism portion disposed in the air passage,

the valve mechanism portion comprising:

a cylinder main body generally centrally disposed inside the inner cap,the cylinder main body formed with a cylindrical first spacecommunicated with the interior of the fuel tank, a second space oftruncated cone shape communicated with the first space from above, andan opening communicated with the second space from above andcommunicated with the interior of the fuel tank at an upper surface, thecylinder main body formed with, on an inner surface that forms thesecond space, plural convex portions elongate in an up/down directionand protruding inwardly with keeping an interval to form a first airpassage between respective convex portions, or on the inner surface,plural concave portions elongate in the up/down direction with keepingan interval to form a second air passage;

a rise/fall member of end closed hollow cylindrical shape having anupper surface and opened at a lower surface, the rise/fall member havinga large-diameter portion at lower part and being accommodated in thefirst space, and a small-diameter portion of truncated cone shape in anouter profile at an upper part and accommodated in the second space;

a spherical valve body placed on an upper surface of the small-diameterportion of the rise/fall member, a laterally outer circumference of thevalve body point contacting with the plural convex portions protruded tothe inner surface of the cylinder main body that forms the second space,or the laterally outer circumference line contacting with the innersurface of the cylinder main body that forms the second space; and

an urge member disposed in a space of the large-diameter portion of therise/fall member, the urge member pushing up the rise/fall member sothat the laterally outer circumference of the valve body placed on thesmall-diameter portion is pressed onto the plural convex portions forurging a point-contact therewith, or pushing up the rise/fall member sothat the laterally outer circumference of the valve body placed on thesmall-diameter portion is pressed onto the inner surface of the cylindermain body for urging a line-contact therewith,

wherein a valve portion is comprised of (a) a part of the laterallyouter circumference of the valve body on the rise/fall member locatedbetween the point-contact positions, where the laterally outercircumference of the valve body is pressed onto the plural convexportions, that is not point contacted, or (b) a part of the laterallyouter circumference of the valve body located between line-contactpositions on the rise/fall member, where the laterally outercircumference of the valve body is pressed onto the inner surface, thatis not line contacted, and (c) a first communication port that is a cutport of the first air passage obtained by cutting the inner surface andthe both convex portions respectively adjacent to the inner surfaceforming the first air passage, by a surface obtained by outwardlyextending a surface formed by connecting a center of the valve body andthe laterally outer circumference, or (d) a second communication portthat is a cut port of the second air passage obtained by cutting a planefor forming concave portions to form the second air passage, by asurface obtained by outwardly extending a surface formed by connecting acenter of the valve body and the laterally outer circumference,

in a state where the laterally outer circumference of the valve body onthe rise/fall member is pressed onto the convex portions for pointcontacting therewith, or in a state where the laterally outercircumference of the valve body on the rise/fall member is pressed ontothe inner surface of the cylinder main body for line contactingtherewith, with increase of a pressure in the fuel tank due to anevaporated gas resulted from a vaporized fuel in the fuel tank, when thepressure in the fuel tank reaches a predetermined pressure value setbased on a first passage resistance or a second passage resistance setup based on an area size of the valve portion constituted of the part ofthe laterally outer circumference not point contacted or the part of thelaterally outer circumference not line contacted and the firstcommunication port or the second communication port, and a magnitude ofan urge force of the urge member that is more than a total weight of thevalve body and the rise/fall member, the evaporated gas rises in thefirst air passage against the first passage resistance, or in the secondair passage against the second passage resistance, passing through thevalve portion, and the rising evaporated gas lowers the valve body andthe rise/fall member downwardly against the urge force of the urgemember, and opens the valve portion to discharge an excessively largepressure in the fuel tank to the exterior of the fuel tank through thefirst space, the second space and the opening.

In a second aspect, the second invention provides a filler cap for afuel tank attached to the fuel tank, the filler cap comprising a capmain body including an outer cap and an inner cap, the filler cap havingan air passage for communicating an interior and an exterior of the fueltank, and a valve mechanism portion disposed in the air passage,

the valve mechanism portion comprising:

a cylinder main body generally centrally disposed inside the inner cap,the cylinder main body formed with a cylindrical first spacecommunicated with the interior of the fuel tank, a second space oftruncated cone shape communicated with the first space from above, andan opening communicated with the second space from above andcommunicated with the interior of the fuel tank at an upper surface, thecylinder main body formed with, on an first inner surface that forms thesecond space, plural convex portions elongate in an up/down directionand protruding inwardly with keeping an interval to form a first airpassage between respective convex portions, or on the first innersurface, plural concave portions elongate in the up/down direction withkeeping an interval to form a second air passage;

a rise/fall member of end closed hollow cylindrical shape having anupper surface and opened at a lower surface to form a space inside, therise/fall member having a large-diameter portion at lower part and beingaccommodated in the first space, and a small-diameter portion oftruncated cone shape in an outer profile at an upper part andaccommodated in the second space;

a spherical valve body placed on an upper surface of the small-diameterportion of the rise/fall member, a laterally outer circumference of thevalve body point contacting with the plural convex portions protruded tothe first inner surface of the cylinder main body that forms the secondspace, or the laterally outer circumference line contacting with thefirst inner surface of the cylinder main body that forms the secondspace;

a coil spring disposed in the space of the rise/fall member, the coilspring pushing up the rise/fall member so that the laterally outercircumference of the valve body placed on the small-diameter portion ispressed onto the plural convex portions for urging a point-contacttherewith, or pushing up the rise/fall member so that the laterallyouter circumference of the valve body placed on the small-diameterportion is pressed onto the first inner surface of the cylinder mainbody for urging a line-contact therewith,

a blow-up member of hollow cylindrical shape including a small-diameterportion loosely inserted into the coil spring accommodated in the spaceof the rise/fall member and formed a small-diameter space, a stepportion having a diameter larger than that of the small-diameter portionand supporting a lower portion of the coil spring on an upper surface,and a large-diameter portion having a diameter larger than that of thestep portion and formed with a large-diameter space communicated withthe small diameter space;

a resistance member for reducing the pressure of an evaporated gas or afuel from the fuel tank, the resistance member including a lower portionof circular shape in a planar view having a communication portcommunicated with the large-diameter space of the blow-up member and thefuel tank, and a cylindrical upper portion centrally studded on an uppersurface of the lower portion, the lower portion being accommodated inthe large-diameter space of the blow-up member to the undersurface ofthe step portion with abutting an upper surface peripheral portion ofthe lower portion, and the upper portion being accommodated in thesmall-diameter space with separated from a second inner surface definingthe small-diameter space,

wherein a valve portion is comprised of (a) a part of the laterallyouter circumference of the valve body on the rise/fall member locatedbetween the point-contact positions, where the laterally outercircumference of the valve body is pressed onto the plural convexportions, that is not point contacted, or (b) a part of the laterallyouter circumference of the valve body located between line-contactpositions on the rise/fall member, where the laterally outercircumference of the valve body is pressed onto the first inner surface,that is not line contacted, and (c) a first communication port that is acut port of the first air passage obtained by cutting the first innersurface and the both convex portions respectively adjacent to the firstinner surface forming the first air passage, by a surface obtained byoutwardly extending a surface formed by connecting a center of the valvebody and the laterally outer circumference, or (d) a secondcommunication port that is a cut port of the second air passage obtainedby cutting a plane for forming concave portions to form the second airpassage, by a surface obtained by outwardly extending a surface formedby connecting a center of the valve body and the laterally outercircumference, and

in a state where the laterally outer circumference of the valve body onthe rise/fall member is pressed onto the convex portions for pointcontacting therewith, or in a state where the laterally outercircumference of the valve body on the rise/fall member is pressed ontothe first inner surface of the cylinder main body for line contactingtherewith, with increase of a pressure in the fuel tank due to theevaporated gas resulted from a vaporized fuel or an expansion of thefuel in the fuel tank, when the pressure in the fuel tank reaches apredetermined pressure value set based on a first passage resistance ora second passage resistance set up based on an area size of the valveportion constituted of the part of the laterally outer circumference notpoint contacted or the part of the laterally outer circumference notline contacted and the first communication port or the secondcommunication port, and a magnitude of an urge force of the coil springthat is more than a total weight of the valve body and the rise/fallmember, the evaporated gas or the expanded fuel rises through thecommunication port of the resistance member, the small-diameter space ofthe blow-up member, a gap between a lower end of the rise/fall memberand the large-diameter portion of the blow-up member, a gap between therise/fall member and the cylinder main body, in the first air passageagainst the first passage resistance or in the second air passageagainst the second passage resistance, passing through the valveportion, and the rising evaporated gas or the rising expanded fuellowers the valve body and the rise/fall member downwardly against theurge force of the coil spring, and opens the valve portion to dischargean excessively large pressure in the fuel tank to the exterior of thefuel tank through the first space, the second space and the opening.

In a third aspect, the third invention provides a filler cap for a fueltank attached to the fuel tank, the filler cap comprising a cap mainbody including an outer cap and an inner cap, the filler cap having anair passage for communicating an interior and an exterior of the fueltank, and a valve mechanism portion disposed in the air passage,

the valve mechanism portion comprising:

a cylinder main body generally centrally disposed inside the inner cap,the cylinder main body formed with a cylindrical first spacecommunicated with the interior of the fuel tank, a second space oftruncated cone shape communicated with the first space from above, andan opening communicated with the second space from above andcommunicated with the interior of the fuel tank at an upper surface, thecylinder main body formed with, on an inner surface that forms thesecond space, plural convex portions elongate in an up/down directionand protruding inwardly with keeping an interval to form a first airpassage between respective convex portions, or on the inner surfaceplural, concave portions elongate in the up/down direction with keepingan interval to form a second air passage;

a rise/fall member of end closed hollow cylindrical shape having anupper surface and opened at a lower surface to form a space inside, therise/fall member having a large-diameter portion at lower part and beingaccommodated in the first space, and a small-diameter portion oftruncated cone shape in an outer profile at an upper part andaccommodated in the second space;

a spherical valve body placed on an upper surface of the small-diameterportion of the rise/fall member in a state a laterally outercircumference capable of point contacting with the plural convexportions protruded to the inner surface of the cylinder main body thatforms the second space, or in a state the laterally outer circumferenceof the valve body capable of line contacting with the inner surface ofthe cylinder main body that forms the second space;

a coil spring disposed in the space of the rise/fall member for pushingup the rise/fall member to allow the laterally outer circumference ofthe valve body placed on the small diameter portion to be pressed ontothe plural convex portions for point contacting therewith, or forpushing up the rise/fall member to allow the laterally outercircumference of the valve body placed on the small-diameter portion tobe pressed onto the inner surface of the cylinder main body for linecontacting therewith;

a blow-up member of hollow cylindrical shape including a small-diameterportion loosely inserted into the coil spring accommodated in the spaceof the rise/fall member and formed a small-diameter apace, a stepportion having a diameter larger than that of the small-diameter portionand supporting a lower portion of the coil spring on an upper surface,and a large-diameter portion having a diameter larger than that of thestep portion, being formed with a large-diameter space communicated withthe small-diameter space, and being accommodated in a space formed in abottom wall of the inner cap; and

a resistance member of circular shape in a planar view having acommunication port communicated with the large-diameter space of theblow-up member and the fuel tank, the resistance member beingaccommodated in the space formed in the bottom wall of the inner capwith abutting to an undersurface of the large-diameter portion of theblow-up member;

wherein a valve portion is comprised of (a) a part of the laterallyouter circumference of the valve body on the rise/fall member locatedbetween the point-contact positions, where the laterally outercircumference of the valve body is pressed onto the plural convexportions, that is not point contacted, or (b) a part of the laterallyouter circumference of the valve body located between line-contactpositions on the rise/fall member, where the laterally outercircumference of the valve body is pressed onto the inner surface, thatis not line contacted, and (c) a first communication port that is a cutport of the first air passage obtained by cutting the inner surface andthe both convex portions respectively adjacent to the inner surfaceforming the first air passage, by a surface obtained by outwardlyextending a surface formed by connecting a center of the valve body andthe laterally outer circumference, or (d) a second communication portthat is a cut port of the second air passage obtained by cutting a planefor forming concave portions to form the second air passage, by asurface obtained by outwardly extending a surface formed by connecting acenter of the valve body and the laterally outer circumference, and

in a state where the rise/fall member and the valve body are lowered bythe urge force that is less than a total weight of the valve body andthe rise/fall member with compressing the coil spring, and the laterallyouter circumference of the valve body on the rise/fall member is notpoint contacted with the plural convex portions, or the laterally outercircumference of the valve body on the rise/fall member is not linecontacted with the inner surface of the cylinder main body therebyopening the valve portion, in an inclined state of the fuel tank, aweight of the rise/fall member and the valve body applied to the coilspring decreases according to the inclined angle, when the coil springexpands its length to have a predetermined length, the valve bodycontacts with the convex portions on the inner surface or contacts withthe inner surface of the cylinder main body, and the fuel spouts, aftera pressure reduction at the communication port of the resistance member,into the space of the rise/fall member from the small-diameter space ofthe blow-up member, so that the spouted fuel pushes up the valve bodyand the rise/fall member thereby closing the valve portion together withthe urge force of the coil spring.

In a fourth aspect, the fourth invention provides A valve body devicefor a fuel tank, comprising a filler cap and a valve mechanism element,the filler cap opening/closing a fill opening provided on an uppersurface of the fuel tank storing a fuel to be supplied to an engine, andinterrupting communication of the fuel tank and an atmosphere throughthe fill opening in a closure of the fill opening,

the valve mechanism element including:

a cylinder main body composed of a cylindrical outer cylinder main bodyportion, an inner cylinder main body portion being generally centrallyconnected to a lower part of the outer cylinder main body portion via aconnection portion and being formed with a storage portion in an upperpart thereof, and an attaching portion having a step stepped belowrelative to the connection portion at a lower end part of the outercylinder main body portion and extending outwardly, the inner cylindermain body portion being formed with a first cylindrical space, a secondspace of truncated cone shape communicated with the first space fromabove, a third space being formed by cutting and removing an inner endpart of the connection portion and a lower end part of the innercylinder main body portion and communicated with the first space frombelow, a fourth space formed by stepping the connecting portion and theattaching portion and connected to the third space from below, and anopening for communicating the second space with the exterior of the fueltank, the cylinder main body being formed with, on a first inner surfacethat forms the second space, plural convex portions elongate in anup/down direction and protruding inwardly with keeping an interval toform a first air passage between respective convex portions, or, on thefirst inner surface, plural concave portions elongate in the up/downdirection with keeping an interval to form a second air passage;

a rise/fall member of end closed hollow cylindrical shape having anupper surface and opened at a lower surface to form a space inside, therise/fall member having a large-diameter portion at lower part and beingaccommodated in the first space, and a small-diameter portion oftruncated cone shape in an outer profile at an upper part andaccommodated in the second space;

a spherical valve body placed on an upper surface of the small-diameterportion of the rise/fall member, in a state a laterally outercircumference of the valve body capable of point contacting with theplural convex portions protruded to the first inner surface of thecylinder main body that forms the second space, or in a state thelaterally outer circumference capable of line contacting with the firstinner surface of the cylinder main body that forms the second space;

a coil spring disposed in the space of the rise/fall member for pushingup the rise/fall member to allow the laterally outer circumference ofthe valve body placed on the small-diameter portion to be pressed ontothe plural convex portions for point contacting therewith, or forpushing up the rise/fall member to allow the laterally outercircumference of the valve body placed on the small-diameter portion tobe pressed onto the inner surface of the cylinder main body for linecontacting therewith;

a blow-up member of hollow cylindrical shape including a small-diameterportion loosely inserted into the coil spring accommodated in the spaceof the rise/fall member and formed a small-diameter apace, a stepportion having a diameter larger than that of the small-diameter portionand supporting a lower portion of the coil spring on an upper surface,and a large-diameter portion having a diameter larger than that of thestep portion and formed with a large-diameter space communicated withthe small-diameter space and accommodated in the fourth space formed inthe cylinder main body;

a resistance member composed of a lower portion of circular shape in aplanar view having a communication port communicated with thesmall-diameter space of the blow-up member and the fuel tank, and acylindrical upper portion centrally studded on an upper surface of thelower portion, the lower portion being accommodated in thelarge-diameter space of the blow-up member to the undersurface of thestep portion with abutting an upper surface peripheral portion of thelower portion, and the upper portion being accommodated in thesmall-diameter space with separated from a second inner surface definingthe small-diameter space;

an attaching member attached to an undersurface of the attaching portionof the cylinder main body, and being formed with a communication pathcommunicated with an opening defined in the fuel tank to be attached tothe fuel tank directly or indirectly, in a state where the blow-upmember that accommodates the lower portion of the resistance member inthe large-diameter space thereof and that is disposed with the upperportion in the small-diameter space thereof, is loosely inserted in thecoil spring disposed in the space of the rise/fall member, and therise/fall member is accommodated in the first space and the second spaceof the cylinder main body that places the valve body on an upper surfacethereof;an accommodation member of hollow cylindrical shape accommodating aporous filter with a space that collects a foreign matter thereof forpreventing entry into the fuel tank, and being attached to the innercylinder main body portion of the cylinder main body; andan upper cap attached to the outer cylinder main body portion from aboveso that a space in the accommodation member and a space in the outercylinder main body portion are communicated with an atmosphere;wherein a valve portion is comprised of (a) a part of the laterallyouter circumference of the valve body on the rise/fall member locatedbetween the point-contact positions, where the laterally outercircumference of the valve body is pressed onto the plural convexportions, that is not point contacted, or (b) a part of the laterallyouter circumference of the valve body located between line-contactpositions on the rise/fall member, where the laterally outercircumference of the valve body is pressed onto the first inner surface,that is not line contacted, and (c) a first communication port that is acut port of the first air passage obtained by cutting the first innersurface and the both convex portions respectively adjacent to the firstinner surface forming the first air passage, by a surface obtained byoutwardly extending a surface formed by connecting a center of the valvebody and the laterally outer circumference, or (d) a secondcommunication port that is a cut port of the second air passage obtainedby cutting a plane for forming concave portions to form the second airpassage, by a surface obtained by outwardly extending a surface formedby connecting a center of the valve body and the laterally outercircumference, andin a state where the rise/fall member and the valve body are lowered bythe urge force that is less than a total weight of the valve body andthe rise/fall member with compressing the coil spring, and the laterallyouter circumference of the valve body on the rise/fall member is notpoint contacted with the plural convex portions, or the laterally outercircumference of the valve body on the rise/fall member is not linecontacted with the first inner surface of the cylinder main body therebyopening the valve portion, in an inclined state of the fuel tank, aweight of the rise/fall member and the valve body applied to the coilspring decreases according to the inclined angle, when the coil springexpands its length to have a predetermined length, the valve bodycontacts with the convex portions on the first inner surface or contactswith the first inner surface of the cylinder main body, and the fuelfrom the fuel tank through the communication path of the attachingmember is reduced the pressure at the communication port of theresistance member and the small-diameter space of the blow-up memberthat accommodates the upper portion of the resistance member, and thenthe fuel spouts into the space of the rise/fall member from thesmall-diameter space of the blow-up member, so that the spouted fuelpushes up the valve body and the rise/fall member thereby closing thevalve portion together with the urge force of the coil spring, andwhen the pressure of the fuel from the fuel tank reaches a predeterminedpressure value, the rise/fall member and the valve body are loweredthereby opening the valve portion, the fuel from the fuel tank flows inthe space of the accommodation member from the first space and thesecond space of the cylinder main body through the opening, the flow-infuel is absorbed in the space inside the filter, in a returnedhorizontal state of the fuel tank, during the pressure in the fuel tankchanging to a negative pressure due to consumption for driving theengine, the fuel absorbed in the filter is stored in the store portionand is returned to the fuel tank.

In a fifth aspect, the fifth invention provides a valve body device fora fuel tank, comprising a filler cap and a valve mechanism element, thefiller cap opening/closing a fill opening provided on an upper surfaceof the fuel tank storing a fuel to be supplied to an engine, andinterrupting communication of the fuel tank and an atmosphere throughthe fill opening in a closure of the fill opening,

the valve mechanism element including:

a cylinder main body composed of a cylindrical outer cylinder main bodyportion, an inner cylinder main body portion being generally centrallyconnected to a lower part of the outer cylinder main body portion via aconnection portion and being formed with a storage portion in an upperpart thereof, and an attaching portion having a step stepped belowrelative to the connection portion at a lower end part of the outercylinder main body portion and extending outwardly, the inner cylindermain body portion being formed with a first cylindrical space, a secondspace of truncated cone shape communicated with the first space fromabove, a third space being formed by cutting and removing an inner endpart of the connection portion and a lower end part of the innercylinder main body portion and communicated with the first space frombelow, a fourth space formed by stepping the connecting portion and theattaching portion and connected to the third space from below, and anopening for communicating the second space with the exterior of the fueltank, the cylinder main body being formed with, on a first inner surfacethat forms the second space, plural convex portions elongate in anup/down direction and protruding inwardly with keeping an interval toform a first air passage between respective convex portions, or, on thefirst inner surface, plural concave portions elongate in the up/downdirection with keeping an interval to form a second air passage;

a rise/fall member of end closed hollow cylindrical shape having anupper surface and opened at a lower surface to form a space inside, therise/fall member having a large-diameter portion at lower part and beingaccommodated in the first space, and a small-diameter portion oftruncated cone shape in an outer profile at an upper part andaccommodated in the second space;

a spherical valve body placed on an upper surface of the small-diameterportion of the rise/fall member, a laterally outer circumference of thevalve body point contacting with the plural convex portions protruded tothe first inner surface of the cylinder main body that forms the secondspace, or the laterally outer circumference of the valve body linecontacting with the first inner surface of the cylinder main body thatforms the second space;

a coil spring disposed in the space of the rise/fall member, the coilspring pushing up the rise/fall member so that the laterally outercircumference of the valve body placed on the small-diameter portion ispressed onto the plural convex portions for urging a point-contacttherewith, or pushing up the rise/fall member so that the laterallyouter circumference of the valve body placed on the small-diameterportion is pressed onto the first inner surface of the cylinder mainbody for urging a line-contact therewith, a blow-up member of hollowcylindrical shape composed of a small-diameter portion loosely insertedinto the coil spring accommodated in the space of the rise/fall memberand formed a small-diameter space, a step portion having a diameterlarger than that of the small-diameter portion and supporting a lowerportion of the coil spring on an upper surface, and a large-diameterportion having a diameter larger than that of the step portion andformed with a large-diameter space communicated with the small-diameterspace and accommodated in the fourth space formed in the cylinder mainbody;

a resistance member composed of a lower portion of circular shape in aplanar view having a communication port communicated with thesmall-diameter space of the blow-up member and the fuel tank, and acylindrical upper portion centrally studded on an upper surface of thelower portion, the lower portion being accommodated in thelarge-diameter space of the blow-up member to the undersurface of thestep portion with abutting an upper surface peripheral portion of thelower portion, and the upper portion being accommodated in thesmall-diameter space with separated from a second inner surface definingthe small-diameter space;

an attaching member attached to an undersurface of the attaching portionof the cylinder main body, and being formed with a communication pathcommunicated with an opening defined in the fuel tank to be attached tothe fuel tank directly or indirectly, in a state where the blow-upmember that accommodates the lower portion of the resistance member inthe large-diameter space thereof and that is disposed with the upperportion in the small-diameter space thereof, is loosely inserted in thecoil spring disposed in the space of the rise/fall member, and therise/fall member is accommodated in the first space and the second spaceof the cylinder main body that places the valve body on an upper surfacethereof;an accommodation member of hollow cylindrical shape accommodating aporous filter with a space that collects a foreign matter thereof forpreventing entry into the fuel tank, and being attached to the innercylinder main body portion of the cylinder main body; andan upper cap attached to the outer cylinder main body portion from aboveso that a space in the accommodation member and a space in the outercylinder main body portion are communicated with an atmosphere;wherein a valve portion is comprised of (a) a part of the laterallyouter circumference of the valve body on the rise/fall member locatedbetween the point-contact positions, where the laterally outercircumference of the valve body is pressed onto the plural convexportions, that is not point contacted, or (b) a part of the laterallyouter circumference of the valve body located between line-contactpositions on the rise/fall member, where the laterally outercircumference of the valve body is pressed onto the first inner surface,that is not line contacted, and (c) a first communication port that is acut port of the first air passage obtained by cutting the first innersurface and the both convex portions respectively adjacent to the firstinner surface forming the first air passage, by a surface obtained byoutwardly extending a surface formed by connecting a center of the valvebody and the laterally outer circumference, or (d) a secondcommunication port that is a cut port of the second air passage obtainedby cutting a plane for forming concave portions to form the second airpassage, by a surface obtained by outwardly extending a surface formedby connecting a center of the valve body and the laterally outercircumference, andin a state where the laterally outer circumference of the valve body onthe rise/fall member is pressed onto the convex portions for pointcontacting therewith, or in a state where the laterally outercircumference of the valve body on the rise/fall member is pressed ontothe first inner surface of the cylinder main body for line contactingtherewith, with increase of a pressure in the fuel tank due to anevaporated gas resulted from a vaporized fuel in the fuel tank or due toan expanded fuel, when the pressure in the fuel tank reaches apredetermined pressure value set based on a first passage resistance ora second passage resistance set up based on an area size of the valveportion constituted of the part of the laterally outer circumference notpoint contacted or the part of the laterally outer circumference notline contacted and the first communication port or the secondcommunication port, and a magnitude of an urge force of the coil springthat is more than a total weight of the valve body and the rise/fallmember, the evaporated gas or the expanded fuel rises via thecommunication port of the resistance member, the small-diameter space ofthe blow-up member, a gap between a lower end of the rise/fall memberand the larger-diameter portion of the blow-up member, and a gap betweenthe rise/fall member and the cylinder main body, in the first airpassage against the first passage resistance or in the second airpassage against the second passage resistance, passing through the valveportion, and the rising evaporated gas or the rising evaporated fuellowers the valve body and the rise/fall member downwardly against theurge force of the coil spring, and opens the valve portion to dischargean excessively large pressure in the fuel tank to the exterior of thefuel tank through the first space, the second space and the opening forabsorbing the fuel in the filter.

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is a schematic view showing an automobile applied with a fillercap for a fuel tank according to the present invention;

FIG. 2 is a plan view showing the filler cap;

FIG. 3 is a backside view showing the filler cap;

FIG. 4 is a longitudinal section view showing an outer cap and inner capconstituting the filler cap in a disassembled state;

FIG. 5 is a backside view showing the outer cap constituting the fillercap;

FIG. 6 is a front view showing the inner cap constituting the fillercap;

FIG. 7 is longitudinal section views and plan views showing a cylindermain body and respective members accommodated therein, which include alongitudinal section view of the cylinder main body (A), a longitudinalsection view of a valve body (B), a longitudinal section view of arise/fall member (C), a longitudinal section view of the rise/fallmember according to other embodiment (D), a backside view of therise/fall member (F), a longitudinal section view of a coil spring (G),a plan view of a spring (H), a section view along a X-X-line in the planview (H) of the spring (I), and a side view of a rivet (I);

FIG. 8 is a longitudinal section view of the filler cap;

FIG. 9 is a longitudinal section view showing principal members in astate where a laterally outer circumference of the valve body ispoint-contacted with the cylinder main body at top portions of theplural convex portions protruded to an inner surface of a second sidewall;

FIG. 10 is a longitudinal section view showing principal members whenthe valve body and the rise/fall member are lowered;

FIG. 11 includes a bottom view (K) sectioned at a position where thelaterally outer circumference of the valve body is point contacted withthe cylinder main body at the top portions of the plural convex portionsprotruded to the inner surface of a second side wall, and a bottom view(L) sectioned at the same position with the valve body removed;

FIG. 12 is a longitudinal section view showing the filler cap having astructure attached to a filler opening by a screw.

FIG. 13 is a longitudinal section view of the principal members a statewhere the laterally outer circumference of the valve body is linecontacted with the cylinder main body at an inner surface of the secondside wall thereof;

FIG. 14 includes a bottom view (N) sectioned at a position where thelaterally outer circumference of the valve body is line contacted withthe cylinder main body at the inner surface of the second side wallthereof, and a bottom view (M) sectioned at the same position with thevalve body removed;

FIG. 15 is a longitudinal section view showing the principal members, ofa second embodiment in which the valve body and the rise/fall membersare formed integrally, in a state where a laterally outer circumferenceof a valve body portion is point contacted with the cylinder main bodyat an inner surface of the second side wall thereof;

FIG. 16 is a longitudinal section view of the principal members in thestate where the rise/fall member is lowered, in the second embodimentshown in FIG. 15;

FIG. 17 is longitudinal section views, plan views and bottom viewsshowing a cylinder main body and respective parts accommodated thereinaccording to the second embodiment, which include a longitudinal sectionview of the cylinder main body (AA), a bottom view sectioned at the sidewall of the cylinder main body (AB), a longitudinal section view of therise/fall member (C), a backside view of the rise/fall member (F), alongitudinal section view of the spring (G), a longitudinal section viewof a blow-up member (OA), a plan view of the blow-up member (OB), abottom view of the blow-up member (OC), a bottom view of a firstresistance member (PA), a plan view of a second resistance member (PB),a longitudinal section view of the first resistance member (PC), alongitudinal section view of the second resistance member (QA), a planview of the second resistance member (QB), a plan view of the lid cap(H), a section view along a X-X-line in the plan view (H) of the lidcap, and a side view of the rivet (j);

FIG. 18 is a longitudinal section view showing the filler cap accordingto the second embodiment in a raised state of the valve body;

FIG. 19 is a longitudinal section view showing the filler cap accordingto the second embodiment in a lowered state of the valve body;

FIG. 20 is a longitudinal section view showing the filler cap accordingto the second embodiment in an inclined state of the valve body;

FIG. 21 is a longitudinal section view showing the filler cap accordingto the third embodiment in a lowered state of the valve body;

FIG. 22 is a longitudinal section view showing the filler cap accordingto the third embodiment in an inclined state of the valve body;

FIG. 23 is a schematic view showing an automobile applied with a valvebody device for a fuel tank according to the present invention;

FIG. 24 is a longitudinal section views, plan views and bottom viewsshowing the respective members in the valve body device according to thesecond embodiment of the valve mechanism element, which include a frontview of a screw (R), a longitudinal section view of an upper cap (SA), aplan view of the upper cap (SB), a bottom view of the upper cap (SC), alongitudinal section view of a filter (TA), a plan view of the filter(TB), a longitudinal section view of an accommodation member (UA), aplan view of the accommodation member (UB), a bottom view of theaccommodation member (UC), a longitudinal section view of the cylindermain body (WA), a plan view of the cylinder main body (WB), a bottomview of the cylinder main body (WC), a longitudinal section view of anattaching member (XA), a plan view of an attaching member (XB), a bottomview of the attaching member (XC);

FIG. 25 is a longitudinal section view showing the valve mechanismelement according to the second embodiment in a horizontal state, withthe valve portion opened;

FIG. 26 is a longitudinal section view of the valve mechanism elementaccording to the second embodiment in an inclined state, with the valveportion closed; and

FIG. 27 is a longitudinal section view of the valve mechanism elementaccording to the second embodiment in a horizontal state, with the valveportion closed.

DESCRIPTION OF THE PREFERRED EMBODIMENT

(1) First Embodiment of a Filler Cap (Refer to FIG. 1 to FIG. 14)

(1-1) First Embodiment of Cylinder Main Body 16 (Valve Body VA, Refer toFIG. 1 to FIG. 12)

In the following, an embodiment of the present invention will bedescribed with reference figures. Firstly, as shown in FIG. 1, a fillercap 10 for a fuel tank 100 according to the present embodiment ismounted on an automobile, an agricultural machinery, a power generator,a lawn mower, a motor cycle, a boat and a ship, a construction machine,a roadwork machine, and so on (hereinafter, referred to as “automobile101” collectively). The filler cap opens/closes a filler opening 98 ofthe fuel tank 100 that supplies a fuel (gasoline in this embodiment) toan engine 99. Meanwhile, an evaporator 95 is connected with a pipearrangement between the fuel tank 100 and the engine 99.

The filler cap 10 is composed of, as shown in FIG. 2, FIG. 3, and FIG.4, a cap main body 14 composed of an outer case 12 having anaccommodation space 12A and formed with convexo-concave portion 11 on aside wall 12C for a manual twist (hereinafter referred to as “outercap”), and an inner case 13 attached into the accommodation space 12A ofthis outer cap 12 (hereinafter to as “inner cap”). This inner cap 13 isequipped with a valve mechanism portion to be described later. Theconvexo-concave portion 11 includes convex portions 11A and concaveportions 11B arranged alternately.

The outer cap 12 has a generally cylindrical shape with a closed endincluding an upper wall 12B and the side wall 12C. The accommodationspace 12A formed by the upper wall 12B and the side wall 12Caccommodates therein the inner cap 13 attached with a filter 38 to bedescribed later.

As shown in FIG. 4, FIG. 6 and FIG. 7, a hollow cylinder main body 16 isstudded at a generally central position on an inner surface side of theinner cap 13 integral with a bottom wall 13A thereof. The cylinder mainbody 16 is composed of a main body portion 16A having a hollowcylindrical shape equipped with a cylindrical first space S1, and an airpassage forming portion 16B that includes a second space S2 of truncatedcone-shaped at an upper part of the main body portion 16A, and has anexternal profile of an truncated cone shape. As mentioned above, thecylinder main body 16 has been originally formed integral with thebottom wall 13A of the inner cap 13, but a separate cylinder main body16 may be fixed to the bottom wall 13A of the inner cap 13.

The cylinder main body 16 is composed of a first side wall 16C, a lowerhorizontal wall 16D provided on the side wall 16C, a second side wall16E provide on the lower horizontal wall 16D, and an upper horizontalwall 16F provided on the second side wall 16E in the named order fromthe bottom. The upper horizontal wall 16F is centrally formed with anopening S3 to communicate a space (including the second space S2) in thecylinder main body 16 and an exterior (atmosphere) of the fuel tank 100.The second side wall 16E has an inner surface 16E1 of which an innerdiameter reduces upwardly.

As shown in FIG. 8, with the inner cap 13 attached to the outer cap 12in an accommodated state, the upper horizontal wall 16F of the cylindermain body 16 is accommodated in a space 12S formed on an undersurface ofthe upper wall 12B of the outer cap 12 for entry, such that the upperhorizontal wall 16F does not abut onto the undersurface of the upperwall 12B with leaving a gap therebetween.

Plural first air passage 15, communicated with the opening S3 and thesecond space S2, is formed on the second side wall 16E of the cylindermain body 16. Described in detail, a transverse plane is formed in aninner surface 16E1 (inner surface defining the second space S2) of thesecond side wall 16E. The transverse plane is for example composed ofplural (for example, eight) convex portions 16T each having a triangleshape and extending in an up/down direction, leaving predetermined gapstherebetween. The convex portions 16T have the same height along theinner surface 16E1 and protrude into the second space S2 so that thefirst air passages 15 are formed between convex portions 16T. That is,the convex portions 16T and the first air passages S15 are alternatelyformed on the inner surface 16E1 of the second side wall 16E of thecylinder main body 16.

As shown in FIG. 7 to FIG. 11, a valve body 22 constituted of aspherical ball made of stainless steel is accommodated in the secondspace S2. The valve body 22 is placed on an upper surface of asmall-diameter portion 23B of the rise/fall member 23 so that its partcontacts with the convex portions 16T to be described later.

The rise/fall member 23 supporting the placed valve body 22 thereon isclosed at an upper surface and is opened at a lower surface to have anend-closed hollow cylindrical shape. It is composed of a lowerlarge-diameter portion 23A and the upper small-diameter portion 23B. Thelarge-diameter portion 23A is accommodated in the cylindrical firstspace S1. The small-diameter portion 23B is accommodated in the secondspace S2, and has a profile of truncated cone shape. When the valve body22 is placed on the small-diameter portion 23B, its upper portion facesthe opening S3. In the space 23S formed in the rise/fall member 23, acoil spring 17 functioning as an urge member (hereinafter, referred toas “spring”) is accommodated. The spring 17 is set to urge the rise/fallmember 23 in the raising direction in an expanded state thereof.

A rivet 34 is inserted into a fixed hole 13G formed in the bottom wall13A of the inner cap 13 (refer to FIG. 6), and a fixed hole 33A formedin the spring 33 as an attaching member. The spring 33 is fixed to thebottom wall 13A by the rivet 34. Meanwhile, the spring 33 is made of ametal material that is hard to rust and does not dissolve with the fuel.

The spring 33 made of a blade spring material is centrally formed withan opening 33B constituting communication path, which forms the airpassage communicated with the space 23S of the rise/fall member 23 andthe fuel tank 100. Meanwhile, the spring 33 is a passage forming memberthat forms the air passage, and also is a fixing tool for fixedlyattaching the filler cap 10 (the cap main body 14) to the fill opening98 of the fuel tank 100.

Accordingly, the valve body 22 is placed on the upper surface of thesmall-diameter portion 23B, and simultaneously, the rise/fall member 23of which the space 23S accommodates the spring 17 therein isaccommodated in the first space S1 and the second space S2 of thecylinder main body 16. Then, the rivet 34 is inserted into the fixedhole 13G of the bottom wall 13A of the inner cap 13 and the fixed hole33A of the spring 33 to fix the spring 33 to the bottom wall 13A of theinner cap 13. Then, with the valve body 22 place on the small-diameterportion 23B of the rise/fall member 23, an urge force of the spring 17pushes up the rise/fall member 23 upwards, so that an outercircumference in a lateral direction, i.e., a laterally outercircumference

CF of the valve body 22 constituting the valve mechanism portion ispressed onto top portions of the plural convex portions 16T by the urgeforce of the spring 17 for making a point-contact. Here, the laterallyouter circumference CF is an outer circumstance of a surface obtained bycutting an upper hemisphere horizontally at ½ position in an up/downdirection (“an outer circumstance of a plane cut horizontally” referredto as “the laterally outer circumference CF of the valve body 22”hereinafter). The top portions are top portions of the plural convexportions 16T, in the protruded direction into the second space S2, thatare protruded into the inner surface 16E1 of the second side wall 16E.

In this embodiment, the valve portion VA is composed of a part CF1 ofthe laterally outer circumference CF of the valve body 22 locatedbetween the point-contact positions and does not make a point-contact,and a first communication port RA which is a cut port of the first airpassage 15. The above part can be expressed otherwise as an outercircumference part. One or more valve portion(s) is (are) included. Thisapplies to all embodiments to be described in the following. At thepoint-contact positions, the laterally outer circumference CF of thevalve body 22 is pressed onto the top portions of the plural convexportions 16T protruded into the inner surface 16E1 of the second sidewall 16. The first communication port RA is obtained by cutting theinner surface forming the first air passage 15 and the both convexportions 16T respectively adjacent to the inner surface, by a surfaceobtained by outwardly extending, more specifically, radially outwardlyextending, or obliquely upwardly extending a surface CS (for example, aconic surface) formed by connecting a center CO of the valve body 22 andthe laterally outer circumference CF.

In the valve portion VA, there are formed a region where

the laterally outer circumference CF of the valve body 22 point contactswith the top points of the plural convex portions 16T of the second sidewall 16E, and a region where it does not contact with the second sidewall 16E. Accordingly, as mentioned above, there is formed the valveportion VA having an extremely small cross-section area, that isconstituted of the part CF1 of the laterally outer circumference CF notpoint contacting, and the first communication port RA.

The cylinder main body 16 is composed of a lower large-diameter portion,and an upper small-diameter portion having a profile of truncated coneshape. FIG. 9 is a longitudinal section view that passes through acenter of the upper horizontal wall 16F having a circular shape in aplaner view. In this embodiment, as shown in FIG. 9, an angle formed byintersecting extension lines that extend upwardly from the top portionsof the convex portions 16T is 60 degrees (preferably, 50 degrees or moreto 70 degrees or less). Thus, as mentioned above, at the ½ position inthe up/down direction of the upper hemisphere of the valve body 22, thelaterally outer circumference CF of the valve body 22 point contactswith the top portions of the plural convex portions 16T.

Meanwhile, the angles formed by the intersected extension lines thatextend upwardly from the top portions of the convex portions 16T areequal at all height positions of the convex portions 16T. In thisembodiment, when the upper horizontal wall 16F is sectionedlongitudinally through a center of the upper horizontal wall 16F, thespace S2 has a profile of trapezoid shape. An angle formed by theintersected extension lines extending upwardly from oblique sides oftrapezoid is also 60 degrees.

However, preferably, this angle is not limited to 60 degrees, but may be50 degrees or more to 70 degree or less. The space S2 sufficiently hasthe truncated cone shape. Here, the rise/fall member 23, and thecylinder main body 16 etc. will be describe in detail with reference toFIG. 8 or FIG. 11. An outer diameter of the large-diameter portion 23Aof the rise/fall member 23 is slightly smaller than a diameter of thefirst space S1 formed by the first side wall 16C of the cylinder mainbody 16. The rise/fall member 23 can move up and down in this firstspace S1. The rise/fall member 23 is raised by the urge force of thespring 17 so that the laterally outer circumference CF of the valve body22 is pressed onto the top portions of the plural convex portions 16T topoint contact therewith. However, a step wall 23E located between thelarge-diameter portion 23A and the small-diameter portion 23B of therise/fall member 23, and a side wall 23F of the small-diameter portion23B do not contact with the lower horizontal wall 16D and the secondside wall 16E of the cylinder main body 16. Accordingly, there is formeda small gap among them.

Meanwhile, a gap 35 is formed between an inner surface of the first sidewall 16C of the cylinder main body 16 and an outer surface of the sidewall 23G of the large-diameter portion 23A of the rise/fall member 23.Convex portions 23T outwardly protruding are formed on a surface of theside wall 23G to extend in an up/down direction. Gaps are formed alsobetween the convex portions 23T and the inner surface of the first sidewall 16C. Accordingly, when the side wall 16C and the convex portions23T contact with each other during rising/falling of the rise/fallmember 23, the small contact surface area therebetween allows therise/fall member 23 to rise or to fall smoothly. Meanwhile, pluralablated portions 23H are formed on the lower end of the side wall 23Gwith a predetermined gap.

Accordingly, the rise/fall member 23 and the valve body 22 are raised bythe urge force of the spring 17 so that the laterally outercircumference CF of the valve body 22 point contacts with the topportions of the plural convex portions 16T. Then, the pressure in thefuel tank 100 increases until it reaches an atmospheric pressure, or 5kPa or more to be described later to realize the state of a positivepressure.

In the positive pressure state, since the first passage resistance(resistance generated when a fluid (evaporated gas of the fuel or thefuel) passes therethrough) based on size of an area of the valve portionVA is large, the point-contact is not released. For this reason, evenwhen the first space S1 communicates with the opening S3 through thefirst air passage 15, due to closure of the valve portion VA, the fluiddoes not come and go between the upper space and the lower space in thisvalve portion VA.

That is, in spite of communication of an interior of the cylinder mainbody 16 with the air, as long as the pressure in the fuel tank 100, inother words, pressure in the space located below the valve portion VA isless than a predetermined set value (for example, less than 5 KPa in theset value), the interior of the cylinder main body 16 located below thevalve portion VA is interrupted from the air by the first passageresistance. Thus, the valve portion VA is closed, which does not allowthe fluid to come and go between the upper space and the lower space ofthe closed valve portion VA.

Meanwhile, in the embodiment (1-1), the pressure value 5 kPa is setbased on the first passage resistance set up based on size of an area ofthe valve portion VA, and magnitude of the urge force of the spring 17that is more than a total weight of the valve body 22 and the rise/fallmember 23.

With increase of the air temperature, the fuel evaporates in the fueltank 100, and the pressure increases in the filler cap 10, The pressurethat flows in from an undersurface opening of the cylinder main body 16also becomes equal to an inner pressure of the fuel tank 100. Asmentioned above, since the cylinder main body 16 is interrupted in itsinterior from the air by the valve portion VA, so it does not dischargethe pressure flowing into its inner space from the undersurface openingto an exterior of the filler cap 10. Thus, the inner pressures are equalbetween the cylinder main body 16 and the fuel tank 100.

Meanwhile, as mentioned above, the first passage resistance is set basedon the area size of the valve portion VA, and combination of the firstpassage resistance and magnitude of the urge force of the spring 17 canbe used to set up an open pressure of the valve portion VA. In thisembodiment, the open pressure is set in 5 kPa or more as mentionedabove. The area of the valve portion VA is extremely small and has forexample 0.002 mm² or more to 0.02 mm² or less, which sets the firstpassage resistance large. An area of a valve portion VB to be describedlater is small likewise, and has the similar sizes.

If the urge force of the spring 17 is excessively large, the rise/fallmember 23 and the valve body 22 cannot be lowered, unless the fuel tank100 is also set in a quite large negative pressure. Accordingly, theurge force of the spring 17 is selected as 1.0 time(s) or more, forexample 1.1 times or more to 2.0 times or less, of the total weight ofthe rise/fall member 23 and the valve body 22. The spring 17 can havethe urge force sufficiently small to raise the valve body 22 and therise/fall member 23 such that the laterally outer circumference CF ofthe valve body 22 is slightly contacted, i.e., point contacted with theplural convex portions 16T formed in the second side wall 16E.

That is, the urge force of the spring 17 is, for example about 1.1 timesof the total weight of the rise/fall member 23 and the valve body 22 inthe engine of free fall type as mentioned above, and for example about2.0 times of the same in the engine of fuel supplying pump type.

With increase of the air temperature, the fuel in the fuel tank 100evaporates to generate gas (Volatile Organic Compounds Gas, abbreviatedto as “VOC gas”), The fuel may expand in the fuel tank 100 filled withthe fuel or the near to this state A fluid pressure of such gas of fuelwill be described. When this fluid pressure is less than for example 5kPa, the VOC gas or the fuel that flows into the gap 35 located betweenthe cylinder main body 16 and the rise/fall member 23 through theopening 33B of the spring 33, also flows into the rise/fall member 23 toincrease the pressure therein. The increased pressure raises therise/fall member 23 and the valve body 22 together with urge force ofthe spring 17, thereby closing the valve portion VA. Thanks to the firstpassage resistance set based on an area size of the valve portion VA, noVOC gas or no fuel in the first space S1 flows out to the exterior ofthe fuel tank 100, i.e., to the exterior of the filler cap 10 throughthe second space S2 and the opening S3.

However, since the interior of the cylinder main body 16 is communicatedwith the air through the opening S3, i.e., through the firstcommunication port RA constituting the valve portion VA, the space inthe cylinder main body 16 is not kept in a sealed and closed state. TheVOC gas flowing into the second space S2 through the gap 35 between thecylinder main body 16 and the rise/fall member 23, or the fuel expandingin the fuel tank 100 filled with the fuel or the near to this state hasthe fluid pressure. When these fluid pressures reach the value that canpass through the valve portion VA, for example 5 kPa or more, the VOCgas or the fuel flowed into the second space S2 located below the valveportion VA is discharged to the exterior of the filler cap 10 from theopening S3 after rising in the first air passage 15. The pressure duringthis discharge lowers the valve body 22 and the rise/fall member 23against the urge force of the spring 17, thereby opening the valveportion VA.

Accordingly, when the filler cap 10 is attached to the fuel tank 100,the pressure in the this fuel tank 100 is not discharged externallyuntil the rise/fall member 23 and the valve body 22 are lowered by theincreased pressure for example, 5 kPa in the fuel tank 100.

Meanwhile, in this embodiment, the outer cap 12, the inner cap 13 andthe rise/fall member 23 are made of the synthetic resin material forexample, nylon6, and the nylon 66 that have solvent resistance to thesolvent fuel, such as gasoline, light oil, ethanol and methanol.

As mentioned above, when the cap main body 14 is attached to the fillopening 98 of the fuel tank 100 by the spring 33, with abutment of thering-like gasket 36 to the fill opening 98, the fill opening 98 isclosed by the cap main body 14 (refer to FIG. 8). Meanwhile in FIG. 4,the filter 38 is a porous filter including an activated carbon filterexcellent in an oil-proof property or a filter made of an urethanesynthetic resin. It filters the air and collects foreign matters such asdirt contained therein to prevent its entry into the fuel tank 100. Withthe filter 38 accommodated in the space 13S around the cylinder mainbody 16 of the inner cap 13, the inner cap 13 is accommodated in theouter cap 12 to fix the outer cap 12 and the inner cap 13. That is, thecylinder main body 16 is inserted into the hollow portion 38A centrallyopened in the filter 38, and the filter 38 is accommodated in the space13S of the inner cap 13, to fix the outer cap 12 and the inner cap 13.

Here, ring-like convex portions 39 are doubly protruded from the upperwall 13B located at peripheral portion of the inner cap 13, and theinner cap 13 is accommodated in the outer cap 12 with heading the convexportion 39. On the other hand, two lines of the adhered ribs 12D areprotruded to an undersurface of the upper wall 12B of the outer cap 12for every predetermined interval, and each adhered rib 12D and eachconvex portion 39 are adhered by an ultrasonic wave.

With the inner cap 13 accommodated in the outer cap 12, there is formeda gap 40 between an inner surface of the side wall 12C of the outer cap12 and an outer surface of the side wall 13C of the inner cap 13 (referto FIG. 8 and FIG. 12). The lower end of the gap 40 opens to form a ventcommunicated with the atmosphere outside the filler cap 10 (exterior ofthe automobile 101).

In FIG. 5 and FIG. 6, there are formed plural grooves 41 with apredetermined interval at each convex portion 39 on the upper surface ofthe inner cap 13. However, the plural adhesion ribs 12D protruded on theouter cap 12 are deviated from the positions (keeping intervals IN)opposing the groove 41 provided in the each convex portion 39 of theinner cap 13, and are not provided at this positions. Thus, the outercap 12 and the inner cap 13 are constituted so that the groove 41provided in the each convex portion 39 is not be closed by the adhesionrib 12D, on adhering of the both caps 12 and 13 by the ultrasonic wave.

In this way, the air passage 43 is formed between the outer cap 12 andthe inner cap 13, which allows the air to be introduced into the fueltank 100 through the filler cap 10. The generated VOC gas or theexpanded fuel increases the inner pressure of the fuel tank 100. Onlywhen the inner pressure reaches the value that can lower the rise/fallmember 23 and the valve body 22, the increased pressure can bedischarged external to the fuel tank 100, through the space 44 betweenthe filter 38 and the undersurface of the outer cap 12, the air passage43 and the gap 40.

Meanwhile, in the pressure unable to lower the rise/fall member 23 andthe valve body 22, the laterally outer circumference CF of the valvebody 22 is point contacted with the top portions of the plural convexportions 16T of the valve body 22, thereby closing the valve portionsVA. Thanks to the first passage resistance, no VOC gas or fuel in thefirst space S1 is discharged to the exterior of the fuel tank 100, i.e.,exterior of the filler cap 10, through the second space S2 and theopening S3.

Accordingly, the valve mechanism portion composed of the cylinder mainbody 16, the rise/fall member 23, the spring 17 and the valve body 22functions as a safety valve. Next, an assembly of the filler cap 10constituted as mentioned above will be described. Meanwhile, it isassumed that on assembling, with the cylinder main body 16 of the innercap 13 inserted into the hollow portion 38A of the filter 38, the innercap 13 is accommodated in the outer cap 12. Each adhesion rib 12D of theouter cap 12 and each convex portion 39 of the inner cap 13 are meltedand fixed by ultrasonic wave to fix the inner cap 13 and the outer cap12.

First, the rise/fall member 23 is accommodated in the space of thecylinder main body 16, for example with the valve body 22 placedthereon. Then, the small diameter portion 23B of the rise/fall member 23with placing the valve body 22 thereon enters the second space S2, andalso the large-diameter portion 23A enters the first space S1.

Next, the spring 17 is accommodated in the space 23S of the rise/fallmember 23, and the rivet 34 is inserted into the fixed hole 13G of thebottom wall 13A of the inner cap 13, and the fixed hole 33A of thespring 33 to fix the spring 33 to the bottom wall 13A. In this way,assembling of the filler cap 10 equipped with the valve mechanismportion is completed. The filler cap 10 thus assembled is attached tothe fill opening 98 in use.

In this state, the spring 17 raises the valve body 22 and the rise/fallmember 23 by its urge force. Consequently, the laterally outercircumference CF of the valve body 22 point contacts with the topportions of the plural convex portions 16T of the second side wall 16Eof the cylinder main body 16. Here, the large first passage resistanceset in the valve portion VA contributes to close the valve portion VAand to hinder a release of the point-contact. Accordingly, no fluidcomes and goes through the first communication port RA constituting thevalve portion VA between the first space S1 and the opening S3.

Next, an operation of the filler cap 10 in a generally horizontal stateof the fuel tank 100 will be described. First, immediately after fillingthe fuel in the fuel tank 100, and attaching the filler cap 10 to thefill opening 98, the pressures are balanced between the interior and theexterior of the fuel tank 100. Accordingly, the spring 17 raises thevalve body 22 and the rise/fall member 23, and the laterally outercircumference CF of the valve body 22 point contacts with the pluralconvex portions 16T of the second side wall 16E, thereby closing thevalve portion VA. Since the first passage resistance does not releasethe point-contact, no fluid comes and goes between the first space S1and the opening S3, which interrupts the communication between interiorand exterior of the fuel tank 100.

That is, there are formed the gap 40, the air passage 43, the space 44,the space 12S, and the opening S3. However, the valve portion VA isclosed by the large first passage resistance resulting from thepoint-contact of the laterally outer circumference CF of the valve body22 with the plural convex portions 16T of the second side wall 16E. Theatmosphere outside the filler cap 10 is prevented from flowing into thefirst space S1 through the opening S3 and the second space S2. There areformed the opening 33B of the spring 33, the first space S1 of thecylinder main body 16, and the gap 35 located between the cylinder mainbody 16 and the rise/fall member 23. However, since the valve portion VAis closed by the first passage resistance of large magnitude, no VOC gasor fuel in the fuel tank 100 is discharged through the opening S3 to theexterior of the fuel tank 100, i.e., exterior of the filler cap 10,thanks to the first passage resistance.

Next, an operation under the risen air temperature during stoppage ofthe engine 99 will be described. The temperature rise causes evaporationof the fuel in the fuel tank 100 leading to generation of the harmfulVOC gas, or expansion of the fuel in the fuel tank 100 filled with thefuel or the near to this state. These increase the inner pressure of thefuel tank 100. However, with the point-contact of the laterally outercircumference CF of the valve body 22 by the spring 17 with the topportions of the plural convex portions 16T, the valve portion VA isclosed as long as the inner pressure of the fuel tank 100 is less thanfor example 5 kPa. As a result, there is no VOC gas or fuel in the firstspace S1 to be discharged through the second space S2 and the opening S3to the exterior of the fuel tank 100, i.e., exterior of the filler cap10, thanks to the first passage resistance.

Accordingly, in spite of the generation of the VOC gas resulted fromevaporation of the fuel in the fuel tank 100, and expansion of the fuelas mentioned above, the VOC gas or the fuel of the automobile 101 issuppressed from discharge. Thus, non-discharge of the fuel and theharmful VOC gas evaporated therefrom exterior the automobile 101 canprevent the environmental pollution.

The air temperature may further rise during stoppage of the engine 99.Then, the fuel in the fuel tank 100 evaporates to further increase thegenerated amount of the VOC gas, and the fuel expands in the fuel tank100 filled with the fuel or the near to this state, both furtherincreasing pressure in the fuel tank 100. When the inner pressurereaches for example 5 kPa or more, the high-pressure VOC gas or theexpanded fuel flows in the first air passage 15 formed betweenrespective convex portions 16T of the second side wall 16E upwardly,against the first passage resistance set based on the area size of thevalve portion VA. The VOC gas or the fuel passes through the valveportion VA where the laterally outer circumference CF of the valve body22 is point contacted with the convex portions 16T. For this reason, theVOC gas or the fuel that flows upwardly passing through the valveportion VA acts on the valve body 22 to depress it from obliquely upwardto obliquely downward.

Accordingly, the valve body 22 and the rise/fall member 23 is lowered bythe VOC gas or the fuel against the urge force of the spring 17, therebyopening the valve portion VA (refer to FIG. 10).

In this way, when pressure in the fuel tank 100 having reached 5 kPa ormore opens the valve portion VA as mentioned above, the excessivelylarge pressure (including the VOC gas and the fuel) in the fuel tank 100is discharged exterior the filler cap 10, i.e., exterior the automobile101 through the opening 33B, the first space S1 (the gap 35), the secondspace S2 (including the first air passage 15), the opening S3, the space12S, the space 44, the air passage 43, and the gap 40.

As result of this discharge, pressure in the fuel tank 100 immediatelyreaches the pressure value of less than 5 kPa to close the valve portionVA as shown in FIG. 8 or FIG. 9, so that the valve mechanism portionfunctions as the safety valve. That is, as mentioned above, when theurge force of the spring 17 raises the rise/fall member 23 and the valvebody 22, the laterally outer circumference CF of the valve body 22 pointcontacts with the top portions of the plural convex portions 16T,thereby closing the valve portion VA. The valve mechanism portion havingthe safety valve function can not only improve the fuel consumption, butalso prevent environmental contamination. As mentioned above, when thepressure in the fuel tank 100 increases to the pressure value set, theVOC gas or the fuel in the first space S1 is discharged through thesecond space S2, and the opening S3 to the exterior of the fuel tank100, i.e., exterior of the filler cap 10. This is because unless the VOCgas or the fuel is discharged, on removing the filler cap 10 from theautomobile 101, there is a risk of the fuel scattering to the exteriorof the automobile 101 by the pressure in the fuel tank 100. In this way,the valve mechanism portion functions as the safety valve.

Next, when the laterally outer circumference CF of the valve body 22 ispoint contacted with the top portions of the plural convex portions 16Tto close the valve portion VA, change of the inner pressure of the fueltank 100 to the negative pressure will be described, which results fromthe fuel consumption for driving the engine 99 of the automobile 101.

Even when the inner pressure of the fuel tank 100 changes to thenegative pressure by consumption of the fuel, the inner pressure of therise/fall member 23 also changes to the negative pressure via theopening 33B of the spring 33. Due to the rise/fall member 23 lowered bythe negative pressure against the spring 17, the valve body 22 is alsolowered to open the valve portion VA.

Then, the atmosphere moves between the opening S3 and the first spaceS1, and flows into the fuel tank 100 through the gap 40, the air passage43, the space 44, the space 12S, the opening S3, the second space S2(including the first air passage 15), the first space S1 (the gap 35)and the opening 33B. Thus, the fuel is supplied to the engine.Accordingly, when the inner pressure of the fuel tank 100 havingreceived the fuel therein changes to an atmospheric pressure state, thevalve body 22 and the rise/fall member 23 raised by the urge force ofthe spring 17 closes the valve portion VA. When there becomes loss ofthe atmosphere flowing into the first space S1 through the opening S3and the second space S2, the inner pressure of the tank changes to thenegative pressure again, which causes the atmosphere to flow into thefirst space S1. Hereinafter, the same operations will be repeated. Theabove-mentioned operation achieved by the negative pressure in the fueltank 100 for driving the engine 99 resulted from consumption, with thevalve portion VA closed, are similarly applied to all the embodimentsrelating to the filler cap 10 and the valve mechanism portion 60 to bedescribe later.

Meanwhile, the filler cap 10 (the cap main body 14) is attached to thefill opening 98 by the spring 33 made from a blade spring. Method orstructure of attaching the filler cap 10 is not limited to the bladesspring type, but can be a screw type. In particular, a screw typeattaching method or structure is not limited, an embodiment of whichwill described hereinafter.

First, as shown in FIG. 12, a hollow outer cylindrical portion 13D as anattaching member is formed at a lower part of the inner cap 13, and afemale screw 13E is formed on an inner surface of the outer cylindricalportion 13D having the space as communication path. The female screw 13Eis meshed with a male screw formed in the fill opening 98 to attach thefiller cap 10 (the cap main portion 14) to the fill opening 98.

An inner cylindrical portion 13F is formed inward of the outercylindrical portion 13D. The inner cylindrical portion 13F is engagedwith an engagement groove 18A formed in a peripheral portion of the cap18 to prevent the rise/fall member 23 accommodated in the first space S1from falling. Thus, the cap 18 fixed to the inner cap 13 holds thespring 17 supporting the rise/fall member 23, resulting in support ofthe rise/fall member 23 in a fall preventing way.

An air passage 18S communicated with the first space S1 is centrallyformed in the cap 18, and a lower portion thereof is communicated withthe interior of the fuel tank 100. That is, a lid body or a lid cap 19for preventing a fluid wave motion is provided in a groove 18B opened onthe undersurface of the cap 18. The undersurface opening of the groove18B is closed by the lid cap 19 except for a part (a fluiddraw/discharge port) 20A thereof communicated with the interior of fueltank 100. A fluid passage 20B communicated with the fluid draw/dischargeport 20A and the air passage 18S are formed above the lid cap 19.

There is provided a centrally opened gasket 21, An outer diameter of thecap 18 is larger than an inner diameter of the opening of the gasket 21.Accordingly, when the inner cylindrical portion 13F is fitted to theengaging groove 18A of the cap 18, a turned piece 18C of the cap 18prevents the gasket 21 from falling. On attaching the filler cap 10 tothe fill opening 98, the male screw formed in the fill opening 98 ismeshed with the female screw 13E formed in an inner wall surface of theouter cylindrical portion 13D. Then, a capsule of the fill opening 98 isabutted to the gasket 21 to seal and close the fill opening 98.

(1-2) Second Embodiment of the Cylinder Main Body 16 (Refer to the ValvePortion VB, FIG. 13 and FIG. 14)

Next, the second embodiment of the cylinder main body 16 will bedescribed with reference to FIG. 13 and FIG. 14. This is also applicableto all the embodiments to be described hereinafter. In the firstembodiment of the cylinder main body 16, the plural convex portions 16Textending in the up/down direction are protruded from the inner surface16E1 of the second side wall 16E, and the first air passage 15 is formedbetween respective convex portions 16T.

However, in this second embodiment, plural second air passages 15Acommunicated with the opening S3 and the second space S2 are formed onthe second side wall 16E of the cylinder main body 16. Described indetail, a transverse plane is formed in an inner surface 16E1 (innersurface defining the second space S2) of the second side wall 16E. Thetransverse plane is for example composed of plural (for example, eight)concave portions 16T (formed by concaving the inner surface 16E1outwardly), each having a triangle shape and extending in an up/downdirection, leaving a predetermined gap therebetween. That is, the firstair passages 15, that are the concave portions 16T and the inner surface16E1 of the second side wall 16E with which the valve body 22 contacted,are alternately formed on the inner surface 16E1 of the second side wall16E of the cylinder main body 16.

Meanwhile, as mentioned above, when the space S2 is sectionedlongitudinally through a center of the upper horizontal wall 16F, it hasa profile of trapezoid shape. An angle formed by intersecting extensionlines that extend upwardly from an oblique side of this trapezoid shapeupwardly is for example 60. The concave portions forming the second airpassage 15A have the same depth over the whole region. Accordingly, asshown in FIG. 13, an angle formed by the intersected extension linesthat extend upwardly from the deepest portions of the concaved portionsis also 60 degrees. However, this angle is not limited to 60 degrees,but may be 50 degrees or more to 70 degree or less. The space S2 issufficiently has the truncated cone shape. The valve portion VB in thissecond embodiment is composed of a part cf2 of the laterally outercircumference part CF of the valve body 22 located between line-contactpositions and does not make the line-contact, and a second communicationport RB which is a cut port of the second air passage 15A. At theline-contact positions, the laterally outer circumference CF of thevalve body 22 is pressed onto the inner surface 16E1 of the second sidewall 16E. The second air passage 15A is obtained by cutting a plane forforming concave portions to form the second air passage, by the surfaceobtained by outwardly extending the surface CS (for example, the conicsurface) formed by connecting the center CO of the valve body 22 and thelaterally outer circumference CF. Thus, the part cf2 of the laterallyouter circumference part CF not line contacting and the second airpassage RB constitute the valve portion VB having an extremely smallarea.

The cylinder main body 16 of the second embodiment thus constituted hasthe operation that is the same as the operation of the first embodiment.Only especially different operations will be described. In a generallyhorizontal state of the fuel tank 100, during stoppage of the engine 99,the valve portion VA is closed when the increasing inner pressure in thefuel tank 100 is less than for example 5 kPa. Such disclosure is broughtby the line-contact of the laterally outer circumference CF of the valvebody 22 with the top portions of the plural convex portions 16T by thespring 17. As a result, no VOC gas or no fuel in the first space S1 isdischarged through the second space S2 and the opening S3 to theexterior of the fuel tank 100, i.e., exterior of the filler cap 10,thanks to the second passage resistance set based on a size of area ofthe valve portion VB (resistance generated during passage of the fluidthrough the valve portion VB).

In the embodiment of (1-2), the pressure value 5 kPa is set based on thesecond passage resistance based on the area size of the valve portionVB, and magnitude of the urge force of the spring 17 that is more than atotal weight of the valve body 22 and the rise/fall member 23.

Accordingly, in spite of generation of the VOC gas resulted fromevaporation of the fuel in the fuel tank 100, and expansion of the fuelas mentioned above, discharge of the VOC gas or the fuel to the exteriorof the automobile 101 is suppressed. Thus, the suppressed discharge ofthe fuel or the harmful VOC gas evaporated therefrom outside theautomobile 101 can prevent the environmental pollution.

Also during stoppage of the engine 99, when the pressure in the fueltank 100 reaches for example 510 a, the high-pressure VOC gas or theexpanded fuel rises in the second air passage 15A of the second sidewall 16E against the second passage resistance. The gas or fuel passesthrough the valve portion VB where the laterally outer circumference CFof the valve body 22 is line contacted with the inner surface 16E1 ofthe second side wall 16E. Accordingly, the rising VOC gas or fuel actson the valve body 22 to depress it downwardly, so that the valve body 22and the rise/fall member 23 are lowered against the urge force of thespring 17. Then, the excessively large pressure (including the VOC gasand the fuel) in the fuel tank 100 is discharged to the exterior of theautomobile 101, through the opening 33B, the first space S1 (the gap35), the second space S2 (including the second air passage 15A), theopening S3, the space 12S, the space 44, the air passage 43 and the gap40, i.e., through the filler cap 10.

As result of this discharge, pressure in the fuel tank 100 immediatelyreaches the value of less than 5 kPa to close the valve portion VB, sothat the valve mechanism portion functions as the safety valve toimprove the fuel consumption and to prevent the environmentalcontamination.

Consumption of the fuel changes inner pressure of the fuel tank 100 tothe negative pressure. The operation in this state is the same as theabove operation of the first embodiment of the cylinder main body 16, soits explanation is omitted.

Meanwhile, in the first embodiment and the second embodiment of thecylinder main body 16, with setting the open pressure of the valveportion VA or VB in for example 5 kPa, in spite of the inclined state ofthe fuel tank 100, the valve portion VA or VB does not open as long asthe pressure in the fuel tank 100 is less than 5 kPa.

In the inclined state of the fuel tank 100, the VOC gas or the fuelflows in the cylinder main body 16, which has a pressure larger than anopen pressure of for example 5 kPa set in the valve portion VA or VB.Operation of such case will be described hereinafter. The valve body 22falls downwardly from the point-contacted state of the valve body 22, orfrom the line-contacted state of the valve body 22 with the cylindermain body 16 by a downward stroke of the rise/fall member 23, asexplained in the cylinder main body 16 of the first embodiment. In thepoint-contacted state, the valve body 22 is point contacted with the topportions of the plural convex portions 16T protruded from the innersurface 16E1 of the second side wall 16E of the cylinder main body 16.In the line-contacted state, the valve body 22 is line contacted withthe inner surface 16E1 of the second side wall 16E. As a result of thedownward falling of the valve body 11, the VOC gas or the fuel in thefuel tank 100 is discharged to the exterior of the automobile 101through the filler cap 10.

In this case, in the second space S2 of the inclined cylinder main body16, the valve body 22 moves onto the inner surface 16E1 located belowthe cylinder main body 16 to be separated away from the longitudinalcentral axis of the second space S2. In view of this, for minimizing theseparation of the valve body 22 away from the longitudinal central axisof the second space S2, ribs or a fences for guidance (both not shown)are provided, with keeping distance (interval) of for example 0.1 mm ormore to 0.4 mm or less from the spherical valve body 22, inwardlyorienting toward the inner surface 16E1 of the second side wall 16E. Theribs or the fences are formed at a lower position than the valve portionVA or VB, so that their inner side ends extend downwardly to be parallelto a central line in the up/down direction of the second space S2 havingthe truncated cone-shaped space.

Provision of the distance (the interval) makes easy the rising andfalling of the valve body 22 guided by the inner end of the ribs or thefences, which stabilizes an opening/closing operation of the valveportion VA or VB. Meanwhile, an up/down movement stroke of the valvebody 22 and the rise/fall member 23 is selected smaller than a half ofthe diameter of the valve body 22.

(2) Second Embodiment of the Valve Body 22 and the Rise/Fall Member 23(Refer to Valve Portion VC, FIG. 7 (D), FIG. 15 and FIG. 16)

Next, the second embodiment of the valve body 22 and the rise/fallmember 23 will be described with reference to FIG. 7 (D), FIG. 15 andFIG. 16. In the first embodiment, the valve body 22 and the rise/fallmember 23 are constituted of separate members, but in the secondembodiment, they are constituted integrally, as described hereinafter.The second embodiment of the valve body 22 and the rise/fall member 23are described, which is applied to the cylinder main body 16 forming thefirst air passage 15 shown in FIG. 7, FIG. 9 and FIG. 10, but it can beapplied to the cylinder main body 16 shown in FIG. 13 and FIG. 14forming the second air passage 15A. The other structures are the sameeach other. However, when the cylinder main body 16 is formed with thesecond air passage 15A as shown in FIG. 13 and FIG. 14, a laterallyouter circumference CP of a hemisphere portion 22A1 of a valve bodyportion 22A in the up/down direction thereof, for example at the ½position (“an outer circumstance of a plane cut horizontally” referredto as “the laterally outer circumference CP of the hemisphere portion22A1” hereinafter), to be explained latter, line contacts with the innersurface 16E1 of the second side wall 16E except the concave portionsforming the second air passage 15A. With understanding the followingexplanation is also understood in this way, explanation is omitted forthe embodiment where the second air passage 15A is formed in thecylinder main body 16.

First, the rise/fall member 23 has a generally hollow cylindrical shapewith a closed end, and is composed of a lower large-diameter portion23A, an upper small-diameter portion 23B, and the valve body portion 22Acentrally formed on the upper surface of the upper wall 23B1 of thesmall-diameter portion 23B. The valve body portion 22A is composed of anupper generally hemisphere portion 22A1, and a lower pillar portion22A2. When sectioned longitudinally, the valve body portion 22A shows anupper semi-circular portion and a lower rectangular portion (refer toFIG. 15).

A step wall 23E located between the large-diameter portion 23A and thesmall-diameter portion 23B of the rise/fall member 23, and a side wall23F of the small-diameter portion 23B do not contact with the lowerhorizontal wall 16D and the second side wall 16E of the cylinder mainbody 16. Accordingly, there are formed small gaps among them.

The urge force of the spring 17 accommodated in the large-diameterportion 23A pushes up the rise/fall member 23 upwards. As a result, thelaterally outer circumference CP of the hemisphere portion 22A1 of thevalve body portion 22A constituting the valve mechanism portion ispressed onto the top portions (the top portions protruded into thesecond space S2) of the plural convex portions 16T to make apoint-contact with such top portions.

Described in detail, the laterally outer circumference CP of an upperhemisphere in the up/down direction, for example at the ½ position ofthe valve body portion 22A, assuming that the upper hemisphere is anupper half of a whole sphere, is point contacted with plural convexportions 16T of the second side wall 16E1 of the cylinder main body 16.

In this embodiment, the valve portion VC is composed of an outercircumference part of the laterally outer circumference CP of the valvebody portion 22A located between the point-contact positions and doesnot make a point-contact, and a first communication port which is a cutport of the first air passage 15. At the point-contact positions, thelaterally outer circumference CP of the valve body portion 22A ispressed onto the top portions of the plural convex portions 16Tprotruded into the inner surface 16E1 of the second side wall 16. Thefirst communication port is obtained by cutting the inner surface 16E1forming the first air passage 15 and the both convex portions 16T eachadjacent to the inner surface 16E1, by a surface obtained by outwardlyextending, more specifically, radially outwardly extending, or obliquelyupwardly extending a surface CU (for example, a conic surface) formed byconnecting a center CN of the valve body portion 22A outwardly assumingthat valve body portion 22A is the upper half of the whole sphere andthe laterally outer circumference CP.

The cylinder main body 16 of this embodiment thus composed has theoperation that is the same as the operation of the first embodiment, soonly different operations of which will be described briefly. In agenerally horizontal state of the fuel tank 100, during stoppage of theengine 99, when the increased inner pressure in the fuel tank 100 isless than for example 5 kPa, the laterally outer circumference CP of thehemisphere portion 22A1 of the valve body portion 22A is point-contactedwith the plural convex portions 16T protruded from the second side wall16 by the spring 17, thereby closing the valve portion VC. As a result,no VOC gas or no fuel in the first space S1 is discharged through thesecond space S2 and the opening S3 to the exterior of the fuel tank 100,i.e., exterior of the filler cap 10, thanks to the first passageresistance (resistance generated during passage of the fluid through thevalve portion) set in the first valve portion (refer to FIG. 15).

Also during stoppage of the engine 99, when the pressure in the fueltank 100 reaches for example 5 kPa, the high-pressure VOC gas or theexpanded fuel rises in the first air passage 15 of the second side wall16E against the first passage resistance, and it passes through thevalve portion VC where the laterally outer circumference CP of the valvebody portion 22A is point contacted with the convex portions 16T of thesecond side wall 16E. Accordingly, the rising VOC gas or fuel acts todepress the rise/fall member 23 downwardly and lowers it against theurge force of the spring 17, thereby opening the valve portion VC (referto FIG. 16). Then, the excessively large pressure (including the VOC gasand the fuel) in the fuel tank 100 is discharged to the exterior of theautomobile 101, through the opening 33B, the first space S1 (the gap35), the second space S2 (including the first air passage 15), theopening S3, the space 12S, the space 44, the air passage 43, and the gap40, i.e., through the filler cap 10. As a result of this discharge,pressure in the fuel tank 100 immediately reaches the value of less than5 kPa to close the valve portion VC, so that the valve mechanism portionfunctions as the safety valve to improve the fuel consumption and toprevent the environmental contamination.

Meanwhile, the valve body portion 22A can be applied to the cylindricalmain body 16 forming the second air passages 15A shown in FIG. 13 andFIG. 14. In this case, a valve portion is composed of the outercircumference part of the laterally outer circumference CP of thehemisphere portion 22A1 of the valve body portion 22A between theline-contact positions and does not make a line-contact, and a secondcommunication port that is a cut port of the second air passage 15A. Atthe line-contact positions, the laterally outer circumference CP of thehemisphere portion 22A1 of the valve body portion 22A is pressed ontothe inner surface 16E1 of the second side wall 16E of the cylinder mainbody 16. The second communication port is obtained by cutting thesurface for forming the concave portions that form the second airpassage 15A by a plane obtained by outwardly extending the surface CU(for example, the conic surface) formed by connecting the center CN ofthe valve body portion 22A outwardly assuming that valve body portion22A is the upper half of the whole sphere and the laterally outercircumference CP.

In this case, when the laterally outer circumference CP of thehemisphere portion 22A1 of the valve body portion 22A is pressed ontoand is line contacted with the inner surface 16E1 of the side wall 16Eof the cylinder main body 16 by the spring 17, the VOC gas generatedfrom evaporation of the fuel or the expanded fuel in the fuel 100increase pressure in the fuel tank 100. When the increased pressure inthe fuel tank 100 reaches for example 5 kPa, the VOC gas or the fuelrises in the second air passage 15A formed in the second side wall 16Eagainst the second passage resistance based on the area size of thevalve portion and passes through the valve portion. Accordingly, therising VOC gas or fuel depresses and lowers the rise/fall member 23against the urge force of the spring 17 to open the valve portion. Then,the excessively large pressure in the fuel tank 100 is dischargedthrough the first space S1, the second space S2 and the opening S3 tothe exterior of the fuel tank 100.

The fuel consumption changes the inner pressure of the fuel tank 100 thenegative pressure. The operations of the two embodiments both using theabove valve body portion 22A in the negative pressure are the same asthe operation of the above embodiment where the valve body 22 is appliedto the cylindrical main body 16 formed with the first air passage 15,the second air passage 15A. Accordingly, the explanation is omitted.

The pressure value 5 kPa in the above embodiment (2) is set based on thefirst passage resistance of the second passage resistance set up basedon the area sizes of the valve portion VC or the valve portion, andmagnitude of the urge force of the urge member 17 that is more than aweight of the rise/fall member 23 having the valve body portion 22A.

(3) Embodiment of the Urge Force of the Spring being Selected Less than1.0 Time(s) of the Total Weight of the Rise/Fall Member 23 and the ValveBody 22, or the Weight of the Rise/Fall Member 23 Having the Valve BodyPortion 22A (Refer to FIG. 1 to FIG. 16)

In the above all embodiments shown in FIG. 1 to FIG. 16, the urge forceof the spring 17 was selected 1.0 time(s) or more e.g., 1.1 times ormore to 2.0 times or less of the total weight of the rise/fall member 23and the valve body 22 (refer to FIG. 8 and FIG. 13), or the weight ofthe rise/fall member 23 having the valve body portion 22A (refer to FIG.15). Hereinafter, the embodiments where the times is selected less than1.0, for example 0.8 or more to 0.93 or less will be described.

For the embodiment where the times is 0.8 or more to 0.93 or less, in agenerally horizontal state the fuel tank 100, the rise/fall member 23and the valve body 22, or the rise/fall member 23 having the valve bodyportion 22A is lowered regardless of the pressure value in the fuel tank100 with compressing the spring 17.

Accordingly, the valve body 22 and the valve body portions 22A do notcontact with the convex portions 16T on the second side wall 16E or withthe inner surface 16E1 of the cylinder main body 16, thereby opening thevalve portions VA, VB and VC etc. (referred to as “valve portion VAetc.” hereinafter).

However, in the inclined state of the fuel tank 100, the total weight ofthe rise/fall member 23 and the valve body 22, or the weight which therise/fall member 23 having the valve body portion 22A applies to thespring 17 decreases, according to this inclined angle until the inclinedangle reaches 90 degrees. The spring 17 increases in an expanded lengththereof. Then, when the spring 17 expands to a predetermined length, thevalve body 22 or the valve body portion 22A contacts with the convexportions 16T on the second side wall 16E or the inner surface 16E1 ofthe cylinder main body 16.

For this reason, in the inclined state of the fuel tank 100, the fuelflows in the gap 35 between the cylinder main body 16 and the rise/fallmember 23 through the opening 33B of the spring 33. Fuel also flows inthe rise/fall member 23 to increase the inner pressure thereof. Theincreased pressure push up the rise/fall member 23 and the valve body22, or the rise/fall member 23 having the valve body portion 22Atogether with the urge force of the spring 17. Consequently, thelaterally outer circumferences CF, CP of an upper hemisphere of thevalve body 22 and the hemisphere portion 22A1 of the valve body portion22A in the up/down direction, e.g. at ½ position are pressed onto thetop portions of the convex portions 16T for point contacting therewith(or the laterally outer circumference CF, CP is pressed onto the innersurface 16E1 of the second side wall 16E for line contacting therewith).Thus, the valve portion VA etc. are closed. The fuel in the first spaceS1 does not flow out to the exterior of the fuel tank 100, i.e.,exterior of the filler cap 10 through the second space S2 and theopening S3, thanks to the first passage resistance or the second passageresistance set in the valve portion VA etc.

As mentioned above, in the inclined state of the fuel tank 100, thevalve portion VA etc. is kept closed until the inner pressure reachesthe predetermined value, for example 5 kPa, so the fuel does not flowout to the exterior of the filler cap 10.

Accordingly, with suppressing discharge of the fuel to the exterior ofthe fuel tank 100, the valve mechanism portion functions as the safetyvalve, which can improve the fuel consumption and prevent theenvironmental contamination.

Also in the inclined state of the fuel tank 100, when pressure of thefuel (liquid pressure) from the fuel tank 100 reaches in the liquidpressure thereof for example 5 kPa, it lowers the rise/fall member 23and the valve body 22 against the urge force of the spring 17, therebyopening the valve portion.

Operation of the embodiment when the fuel tank 100 returns to ahorizontal state (including “a generally horizontal state”) will bedescribed. In this case, the rise/fall member 23 and the valve body 22fall with the total weight thereof, or the weight of the rise/fallmember 23 having the valve body portion 22A, so that the valve portionsVA etc. open regardless of the pressure value in the fuel tank 100.

The pressure value 5 kPa in the above embodiment (3) is set based on thefirst passage resistance or the second passage resistance set up basedon the area size of the valve portion VA etc., and magnitude of the urgeforce of the spring 17 that is less than a total weight of the valvebody 22 and the rise/fall member 23.

(4) Filler Cap 10 of the Second Embodiment (Refer to FIG. 17 to FIG. 20)

The following explanation of the embodiments (4-1) and (4-2) relates tothe filler cap 10 employing the valve portion VA, but they are alsoapplicable to the filler cap 10 using the valve portion VB.

(4-1) Embodiment of the Urge Force of the Spring 17 being 1.0 Time(s) orMore of the Total Weight of the Rise/Fall Member 23 and the Valve Body22 (Refer to FIG. 17 to FIG. 19)

Next, the filler cap 10 of other embodiments will be described withreference to FIG. 17 to FIG. 20. This embodiment employs a cylinder mainbody 16 and members or parts accommodated in the inner cap 13 that arepartially different from those shown in FIG. 7. First, the main body 16is formed with at the lower end of the first side wall 16C thereof astep portion 16G that spreads outwardly from the bottom wall 13A of theinner cap 13. As a result, a space S4 is formed, that has a diameterlarger than that of the first space S1 and is communicated with thefirst space S1, at the bottom wall 13A of the inner cap 13.

A blow-up member 50 having a generally hollow cylindrical shape includesa small-diameter portion 50A, a step portion SOB and a large-diameterportion 50C, The small-diameter portion 50A is loosely inserted into thespring 17 accommodated in the space 23S of the rise/fall member 23(“inserted and arranged with keeping a gap between the interior of thespring 17 and the small-diameter portion”, same as above). The stepportion SOB has a diameter larger than that of the small-diameterportion 50A, and supports a lower portion of the spring 17 on an uppersurface thereof. The large-diameter portion 50C has a diameter largerthan that of the step portion 50B, and is equipped with an upper surfaceabutting onto an undersurface of the step portion 16G. Provision of thestep portion 50B connecting the small-diameter portion 50A and thelarge-diameter portion 50C serves to form, in the blow-up member 50, asmall-diameter space 50S1 and a large-diameter space 50S2 communicatedwith a lower portion of small-diameter space 50S1.

A first resistance member 51 is composed of a lower portion 51A having acircular shape in a planar view, and a cylindrical upper portion 51Bcentrally studded on an upper surface of the lower portion 51A. Thelower portion 51A is accommodated (arranged), with abutting an uppersurface peripheral portion of the lower portion 51A to the undersurfaceof the step portion 50B, in the large-diameter space 50S2 of the blow-upmember 50. Here, the upper portion 51B is accommodated in thesmall-diameter space 50S1 with separated from an inner surface thereofdefining the small-diameter space 50S1. Accordingly, when the upperportion 51B is accommodated in the small-diameter space 50S1, atransverse plane area of the small-diameter space 50S1 is small by avolume corresponding to the upper portion 51B accommodated. Theresultantly increased passage resistance decreases pressure of the VOCgas or the fuel flowing into the small-diameter space 50S1.

Meanwhile, the lower portion 51A of the first resistance member 51 isformed with, on the upper surface and the undersurface thereof,circular-shaped grooves 51C and 51D in the planar view that extend tothe position where the outer diameter thereof does not reach acircumferential end. The above-mentioned upper surface and theundersurface are also formed with two communication ports 51E thatconnect the grooves 51C and 51D. These communication ports 51E makes,due to their small transverse plane areas and the large passageresistances, the passage resistance for the VOC gas or the fuel passinglarge to decrease pressure of the VOC gas or the fuel flowing into thesmall-diameter space 50S1, Meanwhile, the groove 51C has depth of e.g.,0.2 mm, and the groove 51D has depth of e.g., 0.3 mm.

A second resistance member 52 having a circular shaped in a planar viewis accommodated in the large-diameter space 50S2 of the blow-up member50, with abutting an upper surface peripheral portion thereof to theundersurface of the step portion 50B. The second resistance member 52 isformed with, on the upper surface and the undersurface thereof,circular-shaped grooves 52A and 52B in the planar view.

The grooves 52A and 52B extend to the position where the outer diameterthereof does not reach a circumferential end. The above upper surfaceand the undersurface are also formed with two communication ports 52Cthat connect the grooves 51C and 51D. These communication ports 52Cmake, due to their small transverse plane areas and the large passageresistances, the passage resistance for the VOC gas or the fuel passinglarge to decrease pressure of the VOC gas or the fuel flowing into thesmall-diameter space 50S1 through the first communication port 51F ofthe first resistance member 51. Meanwhile, the groove 52A has depth ofe.g., 0.2 mm, and the groove 51D has depth of e.g., 0.3 mm, A passageresistance is formed and set by the transverse plane area of the grooves52A and 52B, and the transverse plane area and length of thecommunication port 52C, which decreases the pressure of the fluidpassing therethrough.

The fuel has viscosity larger than that of gas. In the inclined state ofthe fuel tank 100, the fuel from the fuel tank 100 flows into thesmall-diameter space 50S1 of the blow-up member 50 through thecommunication port 51E of the first resistance member 51. Even when thetemperature rise of the external air increases the pressure of the fuel,the fuel pressure can be decreased thanks to the passage resistanceestablished in the blow-up member 50, the second resistance member 52and the first resistance member 51. Consequently, the small pressureapplied to the valve portion VA (or the valve portion VB) can suppressthe outflow of fuel to the exterior of the filler cap 100 through thevalve portion VA (or the valve portion VB). The embodiment (4) employsthe first resistance member 51, but does not necessarily employ thesecond resistance member 52.

The valve mechanism portion of the embodiment shown in FIG. 17 to FIG.20 is composed of the cylinder main body 16, the rise/fall member 23,the valve body 22, the spring 17, the blow-up member 50, the firstresistance member 51, and the second resistance member 52, etc.

Next, assembly of the filler cap 10 of other embodiments employing suchstructure will be described. This embodiment employs a cylinder mainbody 16 and members accommodated in the inner cap 13 that are partiallydifferent from those shown in FIG. 7. It is assumed that with insertingthe cylinder main body 16 of the inner cap 13 into the hollow portion38A of the filter 38, the inner cap 13 is accommodated in the outer cap12 to fix the inner cap 13 and the outer cap 12.

First, for example, the rise/fall member 23 is accommodated, withplacing the valve body 22 thereon, in the space of the cylinder mainbody 16. Then, the small-diameter portion 23B of the rise/fall member 23enters, with placing the valve body 22 thereon into the second space S2,and also the large-diameter portion 23A enters the first space S1.

Next, the spring 17 is accommodated in the space 23S of the rise/fallmember 23, and the lower portion 51A of the first resistance member 51is accommodate in the large-diameter space 50S2 of the blow-up member50. During such accommodation, an upper surface of the second resistancemember 52 is abutted to an undersurface of the large-diameter portion50C of the blow-up member 50, and an undersurface of the firstresistance member 51, and the upper surface of the large-diameterportion 50C is abutted at a periphery thereof to the undersurface of thestep portion 16G. In this way the small-diameter portion 50A of theblow-up member 50 is accommodated in the spring 17 accommodated in thespace 23S of the rise/fall member 23, and the large-diameter portion 50Cand the second resistance member 52 are accommodated in the space S4formed in the bottom wall 13A of the inner cap 13. In this state, therivet 34 is inserted into the fixed hole 13G formed in the bottom wall13A of the inner cap 13, and the fixed hole 33A of the spring 33 to fixthe spring 33 to the bottom wall 13A.

In this way, assembling of the filler cap 10 equipped with the valvemechanism portion is completed. The filler cap 10 thus assembled isattached to the fill opening 98 in use.

129 Hereinafter, an operation of the filler cap 10 in the embodimentwill be described, in which the urge force of the spring 17 is selected1.0 time(s) or more, for example 1.1 times or more to 2.0 times or lessof the total weight of the rise/fall member 23 and the valve body 22.

First, in a generally horizontal state of the fuel tank 100, duringstoppage of the engine 99, with increase of the air temperature, whenthe increased inner pressure in the fuel tank 100 is less than forexample 5 kPa, the laterally outer circumference CF of the valve body 22is pressed onto the top portions of the convex portions 16T for pointcontacting (or the laterally outer circumference CF is line contactedwith the inner surface 16E1 of the second side wall 16E) by the urgeforce of the spring 17. Thus, the valve portion VA (or the valve portionVB) is closed. As a result, no VOC gas or no fuel in the first space S1is discharged through the second space S2 and the opening S3 to theexterior of the fuel tank 100, i.e., exterior of the filler cap 10,thanks to the first passage resistance set in the valve portion VA (orthe second passage resistance set in the valve portion VB).

The pressure value 5 kPa in the embodiment (4-1) is set based on thefirst passage resistance or the second passage resistance set up basedon the area size of the valve portion VA or the valve portion VB, andmagnitude of the urge force of the urge member 17 that is more than atotal weight of the valve body 22 and the rise/fall member 23. Thepressure value 5 kPa in the embodiments (5-2) and (6-1) to be describedhereinafter is set likewise.

Here, the communication port 52C is formed in the second resistancemember 52, the communication port 51E is formed in the first resistancemember 51, and further the cylindrical upper portion 51B of the firstresistance member 51 exists in the small-diameter space 50S1 of theblow-up member 50, thereby increasing the passage resistance. Theincreased passage resistance decreases the pressure of the VOC gas orthe fuel flowing into the cylindrical main body 16, which suppressesdischarge of the VOC gas or the fuel to the exterior of the tank 100.

Thus, no harmful VOC gas evaporated from the fuel or no fuel isdischarged to the exterior of the automobile 101, which can render thevalve mechanism portion the function as the safety valve, therebyimproving the fuel consumption and preventing the environmentalpollution.

Also during stoppage of the engine 99, with further temperature rise ofthe external air, the VOC gas further increases in the generated amountthereof, or the fuel expands in the fuel tank 100 filled with the fuelor the near to this state, which results in further pressure increase inthe fuel tank 100. When the inner pressure reaches for example 5 kPa,the VOC gas or the fuel from the fuel tank 100 enters the space 23S ofthe rise/fall member 23 through the opening 33B, the groove 52B, thecommunication port 52C and the groove 52A of the second resistancemember 52, the groove 51D, the communication port 51E and the groove 51Cof the first resistance member 51, the large-diameter space 50S2 of theblow-up member 50, and the small-diameter space 50S1 around the upperportion 51B. Here, the pressure of the VOC gas or the fuel is reduced inthe liquid pressure thereof at the communication port 51E of the firstresistance member 51. Simultaneously, the pressure of the VOC gas or thefuel passing through the small-diameter space 50S1 by the upper portion51B of the first resistance member 51 around the upper portion 51B isreduced in the liquid pressure. In this way, the VOC gas or the fuelhaving increased in the flow velocity thereof spouts into the space 23Sof the rise/fall member 23. Accordingly, the VOC gas or the fuel isdischarged to the exterior of the automobile 101, through the gapbetween a side wall lower portion of the large-diameter portion 23A ofthe rise/fall member 23 and the large-diameter portion 50C of theblow-up member 50, the first space S1 (the gap 35), the second space S2(including the first air passage 15 or the second air passage), theopening S3, the space 12S, the space 44, the air passage 43, and the gap40, i.e., through the filler cap 10.

Namely, the high-pressure VOC gas or the expanded fuel rises in thefirst air passage 15 formed between respective convex portions 16T ofthe second side wall 16E (the second air passage 15A formed on the innersurface 16E1 of the second side wall 16E), against the first passageresistance set in the valve portion VA (or the second passage resistanceset in the valve portion VB), passing through the valve portion VA (orthe valve portion VB). Accordingly, the VOC gas or the fuel passesthrough and flows upwardly the first communication port RA (or thesecond communication port RB), which acts on the valve body 22 todepress it from obliquely upward to obliquely downward.

Accordingly, the valve body 22 and the rise/fall member 23 are loweredby the VOC gas or the fuel against the urge force of the spring 17,until the rise/fall member 23 abuts to the upper surface of thelarge-diameter portion 50C of the blow-up member 50 at the side walllower portion of the large-diameter portion 23A of, thereby opening thevalve portion VA (or the valve portion VB) (refer to FIG. 19).

When the pressure in the fuel tank 100 having reached 5 kPa or moreopens the valve portion VA (or the valve portion VB) as mentioned above,the excessive pressure (including the VOC gas or the fuel) in the fueltank 100 is discharged to the exterior of the filler cap 10 i.e.,exterior of the automobile 101,

This immediately changes pressure in the fuel tank 100 to the pressurevalue of less than 5 kPa, and the rise/fall member 23 and the valve body22 are raised by the urge force of the spring 17, so that the laterallyouter circumference CF of the valve body 22 point contacts with the topportions of the plural convex portions 16T (or the laterally outercircumference CF of the valve body 22 line contacts with the innersurface 16E1).

Thus, the valve portion VA (or the valve portion VB) is closed torealize the state as shown in FIG. 18. Thus, the valve mechanism portionfunctions as the safety valve, which can improve the fuel consumptionand prevent the environmental contamination.

The operation for the generally horizontal state of the fuel tank 100explained with reference to FIG. 17 to FIG. 19 can be applied to theoperational explanations for the inclined state of the fuel tank 100.

That is, with setting the open pressure of the valve portion VA (or thevalve portion VB) for example in 5 kPa, in spite of the inclined stateof the fuel tank 100, the valve portion VA (or the valve portion VB)does not open as long as the pressure in the fuel tank 100 is less than5 kPa. Accordingly, the valve mechanism portion functions as the safetyvalve, which can improve the fuel consumption and prevent theenvironmental contamination.

In the inclined state of the fuel tank 100, when the VOC gas or the fuelhaving the open pressure of 5 kPa or more flows in the cylinder mainbody 16, the valve body 22 falls downwardly, Specifically, the valvebody 22 falls downwardly, from the point-contacted state with the topportions of the plural convex portions 16T protruded from the innersurface 16E1 of the second side wall 16E of the cylinder main body 16(or from the line-contacted state with the inner surface 16E1 of thesecond side wall 16E of the cylinder main body 16) by the downwardstroke of the rise/fall member 23. The VOC gas or the fuel in the fueltank 100 is discharged to the exterior of the automobile 101 through thefiller cap 10.

(4-2) Embodiment of the Urge Force of the Spring 17 being Less than 1.0Time(s) of the Total Weight of the Rise/Fall Member 23 and the ValveBody 22 (Refer to FIG. 17, FIG. 19 and FIG. 20)

In the embodiments shown in FIG. 17 to FIG. 19, the urge force of thespring 17 was selected 1.0 time(s) or more e.g., 1.1 times or more to2.0 times or less, of the total weight of the rise/fall member 23 andthe valve body 22 (refer to FIG. 8 and FIG. 13). Hereinafter, theembodiments where the times is selected less than 1.0, for example 0.8or more to 0.93 or less will be described,

In the embodiment where the times is selected 0.8 or more to 0.93 orless, in a generally horizontal state of the fuel tank 100 as shown inFIG. 19, the rise/fall member 23 and the valve body 22 are lowered withthe compressing the spring 17 by the urge force less than the totalweight thereof, regardless of the pressure value in the fuel tank 100.

Accordingly, the valve body 22 is not point contacted with the convexportions 16T formed on the inner surface 16E1 of the second side wall16E (is not line contacted with the inner surface 16E1 of the secondside wall 16E) of the cylinder main body 16, thereby opening the valveportion VA (the valve portion VB).

However, in the inclined state of the fuel tank 100, the total weight ofthe rise/fall member 23 and the valve body 22 applied to the spring 17decreases according to this inclined angle until it reaches 90 degrees,so that the spring 17 increases in an expansion length thereof.Accordingly, with decrease of the weight applied to the spring 17, thespring 17 pushes up the valve body 22 by the urge force thereof. In thepredetermined length of the spring 17, the laterally outer circumferenceCF of the valve body 22 is pressed onto and contacts with the topportions of the convex portions 16T on the second side wall 16E (or withthe inner surface 16E1 of the second side wall 16E) of the cylinder mainbody 16.

Accordingly, as shown in FIG. 20, in the inclined state of the fuel tank100, the fuel enters the space 23S of the rise/fall member 23, throughthe opening 33B of the spring 33, the groove 52B, the communication port52C and the groove 52A of the second resistance member 52, and thegroove 51D, the communication port 51E, the small-diameter space 50S1around the upper portion 51B and the groove 51C of the first resistancemember 51. Here, the fuel pressure is reduced at the communication port51E of the first resistance member 51. Simultaneously, the pressure ofthe fuel passing through the small-diameter space 50S1 around the upperportion 51B of the first resistance member 51 is reduced by the upperportion 51B. In this way, the fuel having increased in the flow velocitythereof spouts into the space 23S of the rise/fall member 23.Accordingly, the spouted liquid pushes up the valve body 22 and therise/fall member 23 quickly together with the urge force of the spring17, thereby closing the valve portion VA (the valve portion VB).

The pressure value 5 kPa in the embodiment (4-2) is set based on thefirst passage resistance (or the second passage resistance) set up basedon the area size of the valve portion VA (or the valve portion VB), andmagnitude of the urge force of the spring 17 that is less than a totalweight of the valve body 22 and the rise/fall member 23. This alsoapplies to the pressure value 5 kPa in the embodiments (5-1) and (6-2)to be described in the following.

As mentioned above, in the inclined state of the fuel tank 100, thevalve portion VA (or the valve portion VB) is kept closed until theinner pressure reaches the predetermined value, for example 5 kPa.Accordingly, no fuel in the first space S1 is discharged to the exteriorof the fuel tank 100, i.e., exterior of the filler cap 10, through thegap between the side wall lower portion of the large-diameter portion23A of the rise/fall member 23 and the blow-up member 50, the firstspace S1 (the gap 35), the second space S2 (including the first airpassage 15) and the opening S3, thanks to the first passage resistance(or the second passage resistance) set in the valve portion VA (or thevalve portion VB).

Accordingly, with suppressing discharge of the fuel to the exterior ofthe fuel tank 100, the valve mechanism portion functions as the safetyvalve, which can improve the fuel consumption and prevent theenvironmental contamination.

Also in the inclined fuel tank 100, when pressure of the fuel (liquidpressure) from the fuel tank 100 reaches for example 5 kPa, it lowersthe rise/fall member 23 and the valve body 22 against the urge force ofthe spring 17, thereby opening the valve portion VA (or the valveportion VB).

When the fuel tank 100 returns to a horizontal state (including “agenerally horizontal state”), the rise/fall member 23 and the valve body22 fall with the total weight thereof to open the valve portion VA (orthe valve portion VB) regardless of the pressure value in the fuel tank100,

(5) Third Embodiment of the Filler Cap 10

The following explanations of the embodiments (5-1) and (5-2) relates tothe filler cap 10 employing the valve portion VA, but they are alsoapplicable to the filler cap 10 employing the valve portion VB.

(5-1) Embodiment of the Urge Force of the Spring 17 being Less than 1.0Time(s) of the Total Weight of the Rise/Fall Member 23 and the ValveBody 22 (Refer to FIG. 21 and FIG. 22)

Next, the other embodiments of the filler cap 10 will be described withreference to FIG. 21 and FIG. 22 by focusing on an operation resultedfrom an especially different structure from the embodiment shown in FIG.17 to FIG. 20.

First, it is assumed that the inner cap 13 is accommodated, withinserting the cylinder main body 16 of the inner cap 13 into the hollowportion 38 a of the filter 38, in the outer cap 12 to fix the inner cap13 and the outer cap 12. For example, the rise/fall member 23 is, withplacing the valve body 22 thereon, accommodated in the space of thecylinder main body 16. Then, the rise/fall member 23 enters the secondspace S2 with placing the valve body 22 on the small-diameter portion23B thereof, and the large-diameter portion 23A of the rise/fall member23 enters the first space S1.

Next, the spring 17 is accommodated in the space 23 s of the rise/fallmember 23, and an upper surface of the second resistance member 52 isabutted to the undersurface of the large-diameter portion 50 c of theblow-up member 50, so that the large-diameter portion 50 c and thesecond resistance member 52 are accommodated in a hollow cylindricalcylinder 13J hung from the bottom wall 13A of the inner cap 13 locatedbelow the step portion 16G.

A circular lid cap 53 is provided, that has small-diameter space 53A, alarge-diameter space 53 b communicated with a lower portion thereof at acentral portion, and a ring-like engagement groove 53C in a planer viewformed on the upper surface thereof. The lid cap 53 engages, in theengagement groove 53C thereof, with the cylinder 13J, so that the uppersurface of lid cap 53 is abutted to the underside surface of thecircumference of the second resistance member 52, for attaching the lidcap 53 to the inner cap 13.

The first resistance member 51 is attached to the lid cap 53 so that theupper portion 51B thereof enters the small-diameter space 53A of the lidcap 53, and the lower portion 51A thereof is accommodated in thelarge-diameter space 53B.

Meanwhile, likewise the structure shown in FIG. 12, the male screwformed on the fill opening 98 is meshed with the female screw 13E formedin an inner wall surface of an outer cylindrical portion 13D formed atthe lower part of the inner cap 13. Thus, the filler cap 10 is attachedto the fill opening 98.

Meanwhile, the valve mechanism portion of the embodiment shown in FIG.21 to FIG. 22 is composed of the cylinder main body 16, the rise/fallmember 23, the valve body 22, the spring 17, the blow-up member 50, thefirst resistance member 51, and the second resistance member 52, etc.

In the above-mentioned embodiment shown in FIG. 21 and FIG. 22, the urgeforce of the spring 17 is selected less than 1.0 time(s) e.g., 0.8 timesor more times to 0.93 times or less of the total weight of the rise/fallmember 23 and the valve body 22. Hereinafter, the operation of thisembodiment will be described.

In the embodiment where the times is selected 0.8 or more to 0.93 orless, in a generally horizontal state of the fuel tank 100 as shown inFIG. 21, the rise/fall member 23 and the valve body 22 are lowered withcompressing the spring 17 by the urge force less than the total weightthereof, regardless of the pressure value in the fuel tank 100.Accordingly, the valve body 22 is not point contacted with the convexportions 16T formed on the inner surface 16E1 of the second side wall16E (is not line contacted with the inner surface 16E1 of the secondside wall 16E) of the cylinder main body 16, thereby opening the valveportion VA (the valve portion VB).

However, in the inclined state of the fuel tank 100, the total weight ofthe rise/fall member 23 and the valve body 22 applied to the spring 17decreases according to this inclined angle until it reaches 90 degrees,so that the spring 17 increases in an expansion length thereof.Accordingly, with decrease of the weight applied to the spring 17, thespring 17 pushes up the valve body 22 by the urge force thereof. In thepredetermined length of the spring 17, the valve body 22 contacts withthe convex portions 16T on the second side wall 16E (the inner surface16E1 of the second side wall 16E) of the cylinder main body 16.

Accordingly, as shown in FIG. 22, in the inclined state of the fuel tank100, the fuel passing through the groove 51D of the first resistancemember 51 enters the small-diameter space 53A of the lid cap 53 throughthe groove 51 after the pressure reduction at the communication port51E, Simultaneously, pressure of the fuel passing through thesmall-diameter space 53A around the upper portion 51B of the firstresistance member 51 is also reduced by the upper portion 51B. The fuelpassing through the groove 52B spouts, after the pressure reduction atthe communication port 52C, into the space 23S of the rise/fall member23 from the small-diameter space 50S1 passing through the groove 52A,the large-diameter space 50S2 of the blow-up member 50. Accordingly, thespouted fuel pushes up the valve body 22 and the rise/fall member 23quickly together with the urge force of the spring 17, so that thelaterally outer circumference CF of the valve body 22 is pressed ontothe top portions of the convex portions 16T for point contacting (or thelaterally outer circumference CF is line contacted with the innersurface 16E1 of the second side wall 16E), Thus, the valve portion VA(or the valve portion VB) is closed.

As mentioned above, in the inclined state of the fuel tank 100, thevalve portion VA (or the valve portion VB) is kept closed until theinner pressure reaches the predetermined value, for example 5 kPa.Accordingly, no fuel gas in the first space S1 is discharged to theexterior of the fuel tank 100, i.e., exterior of the filler cap 10,through the gap between the side wall lower portion of thelarge-diameter portion 23A of the rise/fall member 23 and the blow-upmember 50, the first space S1 (the gap 35), the second space S2(including the first air passage 15 or the second air passage 15A) andthe opening S3, thanks to the first passage resistance (or the secondpassage resistance) set in the valve portion VA (or the valve portionVB).

Accordingly, with suppressing discharge of the fuel to the exterior ofthe fuel tank 100, the valve mechanism portion functions as the safetyvalve, which can improve the fuel consumption and prevent theenvironmental contamination.

Also in the inclined fuel tank 100, when pressure of the fuel (liquidpressure) from the fuel tank 100 reaches for example 5 kPa, it lowersthe rise/fall member 23 and the valve body 22 against the urge force ofthe spring 17, thereby opening the valve portion VA (or the valveportion VB).

When the fuel tank 100 returns to a horizontal state (including “agenerally horizontal state”), the rise/fall member 23 and the valve body22 descend with the total weight thereof to open the valve portion VA(or the valve portion VB) regardless of the pressure value in the fueltank 100.

(5-2) Embodiment of the Urge Force of the Spring 17 being 1.0 Time(s) orMore of the Total Weight of the Rise/Fall Member 23 and the Valve Body22 (Refer to FIG. 21)

Next, the operation of the embodiment constructed as shown in FIG. 21will be described, in which the urge force of the spring 17 is selected1.0 time(s) or more, for example 1.1 times or more to 2.0 times or less,of the total weight of the rise/fall member 23 and the valve body 22.

First, in a generally horizontal state of the fuel tank 100, duringstoppage of the engine 99, with increase of the air temperature, whenthe increased inner pressure in the fuel tank 100 is less than forexample 5 kPa, the laterally outer circumference CF of the valve body 22is pressed onto and point contacted with the top portions of the convexportions 16T (or is line contacted with the inner surface 16E1 of thesecond side wall 16E) by the urge force of the spring 17. Thus, thevalve portion VA (or the valve portion VB) is closed. As a result, noVOC gas or no fuel in the first space S1 is discharged through thesecond space S2 and the opening S3 to the exterior of the fuel tank 100,i.e., exterior of the filler cap 10, thanks to the first passageresistance (or the second passage resistance) set in the valve portionVA (or the valve portion). Here, the communication port 51E is formed inthe first resistance member 51, the cylindrical upper portion 51B of thefirst resistance member 51 exists in the small-diameter space 53A of thelid cap 53, and the communication port 52C is formed in the secondresistance member 51, thereby increasing the passage resistance. Theincreased passage resistance decreases the pressure of the VOC gas orthe fuel flowing into the cylinder main body 16, which suppressesdischarge of the VOC gas or the fuel to the exterior of the tank 100.

Thus, non-discharge of the harmful VOC gas evaporated from the fuel orthe fuel to the exterior of the automobile 101 renders the valvemechanism portion the safety valve function, which results inimprovement of the fuel consumption and prevention of the environmentalpollution.

Also during stoppage of the engine 99, with further temperature rise ofthe external air, the VOC gas further increases in the generated amountthereof, or the fuel expands in the fuel tank 100 filled with the fuelor the near to this state, leading to the further pressure increase inthe fuel tank 100. When the inner pressure reaches for example 5 kPa,the VOC gas or the fuel from the fuel tank 100 enters the space 13S ofthe rise/fall member 23 through the groove 51D, the communication port51E and the groove 51C of the first resistance member 51, thesmall-diameter space 53A around the upper portion 51, the groove 52B,the communication port 52C and the groove 52A of the second resistancemember 52, and the large-diameter space 50S2 and the small-diameterportion 50S1 of the blow-up member 50. The fuel or the VOC gas isdischarged to the exterior of the automobile 101, through the gapbetween the side wall lower portion of the large-diameter portion 23A ofthe rise/fall member 23, and the blow-up member 50, the first space S1(the gap 35), the second space S2 (including the first air passage 15 orthe second air passage 15A), the opening S3, the space 12S, the space44, the air passage 43, and the gap 40, i.e., through the filler cap 10.

Namely, the high-pressure VOC gas or the expanded fuel rises in thefirst air passage 15 (or the second the air passage 15A) formed on thesecond side wall 16E against the first passage resistance (or the secondpassage resistance) set in the valve portion VA (or the valve portionVB), passing through the valve portion VA (or the valve portion VB).Accordingly, the VOC gas or the fuel passes through and flows upwardlythe valve portion VA (or the valve portion VB), which acts on the valvebody 22 to depress it from obliquely upward to obliquely downward.

Accordingly, the valve body 22 and the rise/fall member 23 are loweredby the VOC gas or the fuel against the urge force of the spring 17,until the side wall lower portion of the large-diameter portion 23A ofthe rise/fall member 23 abuts to the upper surface of the large-diameterportion 50C of the blow-up member 50, thereby opening the valve portionVA (or the valve portion VB) (refer to FIG. 21).

When the pressure in the fuel tank 100 having reached 5 kPa opens thevalve portion VA (or the valve portion VB) as mentioned above, theexcessive pressure (including the VOC gas or the fuel) in the fuel tank100 is discharged to the exterior of the automobile 101 through thefiller cap 10.

This immediately changes pressure in the fuel tank 100 to the pressurevalue less than 5 kPa, and the rise/fall member 23 and the valve body 22are raised by the urge force of the spring 17, so that the laterallyouter circumference CF of the valve body 22 point contacts with the topportions of the plural convex portions 16T (or the similarly outercircumference CF line contacts with the inner surface 16E1 of the secondside wall 16E), thereby closing the valve portion VA (or the valveportion VB). Thus, the valve mechanism portion functions as the safetyvalve, which can improve the fuel consumption and prevent theenvironmental contamination.

That is, with setting the open pressure of the valve portion VA (or thevalve portion VB) for example in 5 kPa, in spite of the inclined stateof the fuel tank 100, the valve portion VA (or the valve portion VB)does not open as long as the pressure in the fuel tank 100 is less than5 kPa. Accordingly, the valve mechanism portion functions as the safetyvalve, which can improve the fuel consumption and prevent theenvironmental contamination.

In the inclined state of the fuel tank 100, when the VOC gas or the fuelhaving the open pressure of 5 kPa or more flows in the cylinder mainbody 16, the valve body 22 falls downwardly. Specifically, the valvebody 22 falls downwardly from the point-contacted state with the topportions of the plural convex portions 16T protruded from the innersurface 16E1 of the second side wall 16E of the cylinder main body 16(or from the line-contacted state with the inner surface 16E1) by thedownward stroke of the rise/fall member 23. The VOC gas or the fuel inthe fuel tank 100 is discharged to the exterior of the automobile 101through the filler cap 10.

Meanwhile, the embodiment (5) employs the second resistance member 52,but employment of the first resistance member 51 is not essential.

(6) First Embodiment of the Valve Mechanism Element 60

The following explanations of the embodiments (6-1) and (6-2) relate tothe valve mechanism element 60 employing the valve portion VA, but theyare also applicable to the valve mechanism element 60 employing thevalve portion VB.

(6-1) Embodiment of the Urge Force of the Spring 17 being 1.0 Time(s) orMore of the Total Weight of the Rise/Fall Member 23 and the Valve Body22 (Refer to FIG. 1 to FIG. 23)

The above-mentioned all embodiments shown in FIG. 1 to FIG. 22 relate tothe filler cap 10 shown in FIG. 1 schematically showing the automobile101. However, an element that is the same as this filler cap 10 can beused as the valve mechanism element 60 (refer to FIG. 23), which will bedescribed hereinafter.

First, as shown in FIG. 23, a filler cap 61 different from the fillercap 10 opens/closes the fill opening provided on the upper surface ofthe fuel tank 100, on pouring gasoline G as the fuel into the fuel tank100.

That is, the interior of the fuel tank 100 and the atmosphere arecommunicated through the fill opening, which allows the gasoline G topour in the fuel tank 100 through the filler cap 61. Closing the fillercap 61 interrupts the communication of the fuel tank 100 with theatmosphere through the fill opening.

The valve-mechanism element 60 is provided on the upper surface of thefuel tank 100, that is of structure the same as the filler cap 10explained with reference to FIG. 1 from FIG. 22. A valve body device ofthe fuel tank 100 composed of the filler cap 61 and the valve mechanismelement 60 mentioned above. The gasoline G in the fuel tank 100 issupplied to the engine 99 through the piping 63 by the pump 62.

In the valve body device thus constituted, the operation of the valvemechanism element 60 will be described, where the urge force of thespring 17 is selected 1.0 time(s) or more, for example 1.1 times or moreto 2.0 times or less, of the total weight of the rise/fall member 23 andthe valve body 22.

First, in a generally horizontal state or the inclined state of the fueltank 100, during stoppage of the engine 99, in spite of increase of theinner pressure in the fuel tank 100 resulted from the increased airtemperature, as long as it is less than for example 5 kPa, as mentionedabove, the laterally outer circumference CF of the valve body 22 ispressed onto and point contacted with the top portions of the convexportions 16T (or the laterally outer circumference CF is line contactedwith the inner surface 16E1 of the second side wall 16E) by the urgeforce of the spring 17. Thus, the valve portion VA (or the valve portionVB) is closed. As a result, no VOC gas or no fuel in the first space S1is discharged through the second space S2 and the opening S3 to theexterior of the fuel tank 100, i.e., exterior of the valve mechanismelement 60, thanks to the first passage resistance set in the firstcommunication port RA (the second passage resistance set in the secondcommunication port RB).

Also in a generally horizontal state or the inclined state of the fueltank 100, during stoppage of the engine 99, with further temperaturerise of the external air, the VOC gas further increases in the generatedamount thereof, or the fuel expands in the fuel tank 100 filled with thefuel or the near to this state, which causes the further pressureincrease in the fuel tank 100. When the inner pressure reaches forexample 5 kPa, the VOC gas or the fuel from the fuel tank 100 rises inthe first air passage 15 (or the second the air passage 15A) formed onthe second side wall 16E of the cylinder main body 16, passing throughthe valve portion VA (or the valve portion VB). This rising VOC gas orfuel depresses the valve body 22 downwardly and the excessive pressure(including the VOC gas or the fuel) in the first space S1 is dischargedto the exterior of the fuel tank 100.

(6-2) Embodiment of the Urge Force of the Spring 17 being Less than 1.0Time(s) of the Total Weight of the Rise/Fall Member 23 and the ValveBody 22 (Refer to FIG. 1 to FIG. 23)

Next, an operation of the valve mechanism element 60 in the embodimentwill be described, in which the urge force of the spring 17 is selectedless than 1.0 time(s), for example 0.8 times or more to 0.93 times orless of the total weight of the rise/fall member 23 and the valve body22.

In the embodiment where the times is selected 0.8 or more to 0.93 orless, in a generally horizontal state the fuel tank 100, the rise/fallmember 23 and the valve body 22 are lowered with compressing the spring17 by the urge force less than the total weight thereof, regardless ofthe pressure value in the fuel tank 100. Accordingly, the valve body 22is not contacted with the convex portions 16T faulted on the innersurface 16E1 of the second side wall 16E (or with the inner surface16E1) of the cylinder main body 16, thereby opening the valve portion VA(or the valve portion VB).

However, when the fuel tank 100 is inclined, the weight of the rise/fallmember 23 and the valve body 22 applied to the spring 17 decreasesaccording to this inclined angle until it reaches 90 degrees. As aresult, the spring 17 compressed in the horizontal state of the fueltank 100, increases in its expansion length with increase of theinclined angle. Accordingly, with decrease of the weight applied to thespring 17, the spring 17 pushes up the valve body 22 by the urge forcethereof. In the predetermined length of the spring 17, the laterallyouter circumference CF of the pushed-up valve body 22 is pressed ontoand point contacts with the top portions of the convex portions 16Tformed on the inner surface 16E1 of the second side wall 16E (or linecontacts with the inner surface 16E1) of the cylinder main body 16.

Accordingly, in the inclined state of the fuel tank 100, as mentionedabove, the fuel flows in the rise/fall member 23 to increase the innerpressure thereof, until the inner pressure of the fuel tank 100 reachesto 5 kPa. The increased pressure pushes up the rise/fall member 23 andthe valve body 22 together with the urge force of the spring 17, therebyclosing the valve portions VA (or the valve VB). The fuel in the firstspace S1 does not flow out to the exterior of the fuel tank 100, i.e.,the exterior of the valve mechanism element 60 through the second spaceS2 and the opening S3, thanks to the first passage resistance (or thesecond passage resistance) set in the valve portion VA (or the valveportion VB).

Accordingly, with suppressing discharge of the fuel to the exterior ofthe fuel tank 100, the valve mechanism portion of the valve mechanismelement 60 functions as the safety valve, which can improve the fuelconsumption and prevent the environmental contamination.

Also in the inclined fuel tank 100, when pressure of the fuel (liquidpressure) from the fuel tank 100 reaches for example 5 kPa, it lowersthe rise/fall member 23 and the valve body 22 against the urge force ofthe spring 17, thereby opening the valve portion VA (or the valveportion VB).

Meanwhile, when the fuel tank 100 returns to a horizontal state(including “a generally horizontal state”), the rise/fall member 23 andthe valve body 22 fall with the total weight thereof to open the valveportion VA (or the valve portion VB), regardless of the pressure valuein the fuel tank 100.

(7) Second Embodiment of the Valve Mechanism Element 60 (Refer to FIG.24 to FIG. 27)

Next, the second embodiment of the valve mechanism element 60 will bedescribed with reference to FIG. 24 to FIG. 27, where a valve bodydevice of the fuel tank 100 is constituted of the filler cap 61 and thevalve-mechanism element 60 (refer to FIG. 23). Here, the valve body 22,the rise/fall member 23, the spring 17, the blow-up member 50, and thefirst resistance member 51 shown in FIG. 17 are omitted in FIG. 24, butthey are employed for the valve mechanism element 60.

(7-1) Embodiment of the Urge Force of the Spring 17 being Less than 1.0Time(s) of the Total Weight of the Rise/Fall Member 23 and the ValveBody 22 (Refer to FIG. 24 to FIG. 26)

In the following embodiment shown FIG. 24 to FIG. 26, urge force of thespring 17 is less than 1.0 time(s) or less, for example 0.8 times ormore to 0.93 times or less, of the total weight of the rise/fall member23 and the valve body 22, which will be described below.

The cylinder main body 70 is composed of an inner cylinder main bodyportion 71 accommodating the valve body 22 and the rise/fall member 23therein, a hollow cylindrical outer cylinder main body portion 72 formedwith a cut part 72A and openings 72B at an upper end thereof, aconnection part 73 connecting the inner cylinder main body portion 71and the outer cylinder main body portion 72, and an attaching portion 74at a lower part of the cylinder main body portion 72. The cut part 72Ais formed by removing an outer part of entire circumference to bethinned for allowing the fluid passage therethrough. The openings 72Bare defined by four cut parts.

The attaching portion 74 is formed at the lower part of the innercylinder main body portion 71 to extend outwardly with a step relativeto the connection portion 73. Accordingly, the inner cylinder main bodyportion 71 is connected to the lower portion of the outer cylinder mainbody portion 72 in a generally center position of the outer cylindermain body portion 72.

The inner cylinder main body portion 71 is composed of a cylindricalfirst side wall 71C, a lower horizontal wall 71D internally provided atan upper part of the first side wall 71C, a second side wall 71Eprovided at an upper part of the lower horizontal wall 71D, and an upperhorizontal wall 71F provided at an upper part of the second side wall71E. The upper horizontal wall 71F is centrally forming with an opening71 s that communicates the space in the inner cylinder main body portion71 and exterior of the fuel tank 100 (atmosphere). The first side wall71C, the lower horizontal wall 71D and the second side wall 71Econstructs a storage portion 71A for the fuel leaked to be describedlater. The second side wall 71E has an inner surface 71E1 of which aninner diameter decreases upwardly.

Meanwhile, the inner cylinder main body portion 71 is formed, on theinner surface 71E of the second side wall 71E (the inner surface 71Eforms the second space S32 to be described later), with plural convexportions 71T. The plural convex portions 71T are long in the up/downdirection, and are protruded inwardly with leaving predetermined gaps. Afirst air passage is formed between the respective convex portions 71T.

An inner end part of the connection portion 73, i.e., a lower end partof the first side wall 71C of the inner cylinder main body portion 71 iscut and removed to form a third space S33. This third space S33 iscommunicated with a second space S32 of a truncated cone-shape through afirst cylindrical space S31 in the inner cylinder main body portion 71.A lower part of the attaching portion 74 is removed to form a ring-likeaccommodation groove 74A on the undersurface thereof. A thick portion82T of circular-shape in a planar view is centrally formed on theattaching member 82, by stepping the connection portion 73 and theattaching portion 74. With fitting the thick portion 82T into a fourthspace S34 communicated with the third space S33 from a lower location,the cylinder main body 70 is fixed to the attaching member 82 usingbolts 80 and nuts 81. Furthermore, the attaching portion 74 is formedwith, at an intermediate position between the accommodation groove 74Aand a circumferential end thereof, plural attaching holes 74B forallowing the bolt 80 to pass therethrough. That is, for fixing thecylinder main body 70 to the attaching member 82 by the bolt 80 and thenut 81, with accommodating an O-ring 86 in the accommodation groove 74A,the attaching hole 74B and the attaching hole 82B defined in theattaching member 82 are coincided. Then, the bolts 80 are inserted intothe both holes, and the nuts 81 are screwed to the bolts for fixing(refer to the left half of the attaching member 82 shown in the lowestpart of FIG. 24, and the left half of FIG. 25 and FIG. 26). When thefixation is performed by an ultrasonic adhesion, adhesion ribs 82A ofcircular shape in a planar view, studded on the upper surface of theattaching member 82, are fitted into the accommodation groove 74A. Inthis state, the ultrasonic adhesion is performed on the surface of thecylinder main body 70 formed with the accommodation groove 74A to fixthe cylinder main body 70 to the attaching member 82 (refer to the righthalf of the attaching member 82 shown in the lowest part of FIG. 24, andthe right half of FIG. 25, and FIG. 26).

The attaching member 82 is formed of, at the lower part, a hollowcylindrical cylinder portion 82C that communicates with a space(communication path) 82S1 communicated with a communication port 82S2formed in the thick portion 82T thereof. A female screw 82D is formed onan inner surface of the cylindrical portion 82C. An attaching cylinderportion 10011 of hollow shape is formed on the upper surface of the fueltank 82, that is equipped with a space communicated with an openingdefined on an upper surface of the fuel tank 100. Meshing the male screwformed on the outer surface of the attaching cylinder portion 100B withthe female screw 82D formed in the cylindrical part 82C allows to attachthe valve mechanism element 60 to the fuel tank 100.

An accommodation member 75 is arranged in the space of the outercylinder main body portion 72, with leaving a gap between a side wall ofthe outer cylinder main body portion 72 and the accommodation member 75itself. The accommodation member 75 accommodates therein a porous filter79 such as an activated carbon filter excellent in an oil resistance, ora filter made of a urethane synthetic resin. On introducing theatmosphere into the fuel tank 100 for driving the engine 99, the filter79 filters the atmosphere to collect of the foreign matters, such asdirt contained therein, thereby preventing its entry into the fuel tank100. The accommodation member 75 is fitted, at a lower part thereof, toan upper part of the first side wall 71C of the inner cylinder main bodyportion 71 for attaching thereto. Here, the accommodation member 75 andthe cylinder main body 70 are separately prepared followed byunification, but they can be originally unified.

Described in detail, the accommodation member 75 of hollow cylindricalshape includes a large-diameter portion 76 formed with a large-diameterspace 76S and openings 76A, a small-diameter portion 78 formed with asmall-diameter space 78S, and a connection portion 77 connecting thelarge-diameter part 76 and the small-diameter portion 78. The openings76A are formed by cutting and removing the upper part at four pointswith leaving predetermined gaps for allowing the fluid passage. Theconnection portion 77 is formed with an opening 77S of diameter smallerthan the small-diameter space 78S. The connection portion 77 has anupper surface inclined downwardly so that its thickness is graduallythinned from an outer location to an inner location. On an upper surfaceof the connection portion 77, four ribs 77A are formed with leavingpredetermined intervals therebetween. The ribs 77A extend from the innersurface of the large-diameter part 76 in the length not to reach aninner end of the opening 77S of the connection part 77, and they haveupper surfaces horizontally formed to support the filter 79horizontally.

When the inner cylinder main body portion 71 the inner cylinder mainbody portion 71 is attached to the accommodation member 75, withabutting the upper part of the first side wall 71C of the inner cylindermain body portion 71 to the inner surface of the small-diameter portion78 and the undersurface of the connection portion 77, the inner cylindermain body portion 71 is fitted to the accommodation member 75.

An upper lid or an upper cap 88 includes an end closed cylindrical upperwall 88A having a circular shape in a planar view and an arc shape in alongitudinally sectioned view, and a side wall 88B hung down from ancircumferential end of the upper wall 88A. The upper cap 88 and relatedmembers are constructed as below. The upper cap 88 is attached to anupper parts of the outer cylinder main body portion 72 of the cylindermain body 70. In this state, the space in the accommodation member 75 iscommunicated with the atmosphere through the opening 76A of theaccommodation member 75, the opening 72B and the removed portion 72A ofthe outer cylinder main body portion 72 of the cylinder main body 70,and the concave portion 88D of the upper cap 88.

At two opposed locations of the upper cap 88, guide members 89 areformed to extend from a circumference portion of an upper wall 88Ainwardly. The guide member 89 is defined with, on an undersurface of theupper wall 88A, an insertion hole 89A having a diameter larger than theouter diameter of a shaft portion of a screw 90 and is smaller than anouter diameter of the head portion thereof. An insertion hole 88C isdefined, which is concentric with the communication hole 89A and has adiameter larger than the communication hole 89A (larger than a headportion of the screw 90). Concave portions 88D are formed on an innersurface of the side wall 88B of the upper cap 88 every 45 degrees.

At two opposing locations on the filter 79, concave portions 79A ofsemi-circular in a planar view are formed in the up/down direction. Theaccommodation member 75 is formed on the large-diameter portion 76, twoconcave portions 76B of semicircular shape in a planar view and extendin the up/down direction, at two locations coinciding with a shape ofthe filter 79 that is accommodating. The outer cylinder main bodyportion 72 is formed with, at an upper part thereof, a swell portion 72Cof semi-circular shape in a planar view and extending in the up/downdirection, at two opposed locations coinciding with a shape of thelarge-diameter portion 76 of the accommodation member 75 that isaccommodating. The swell portion 72C is formed with, the thread grooves72D meshed by the screw 90.

Here, length of the spring 17 arranged in the space 23S of the rise/fallmember 23 will be described. The length of the spring 17 is calculatedby adding a dimension between an undersurface of the step wall 23E ofthe rise/fall member 23, and an upper surface of the step portion 50B ofthe blow-up member 50 (same for the embodiment of FIG. 17 to FIG. 27,between the undersurface of the step wall 23E and the upper surface ofthe spring 33 for the embodiment of FIG. 7 to FIG. 11, and between theundersurface of the step wall 23E and the upper surface of the cap 18for the embodiment of FIG. 12) and 1.0 time(s) or more to 3.0 times orless times of the movable stroke of the rise/fall member 23. Also, thelength of the spring 17 is determined, by being compressed by the totalweight of the valve body 22 and the rise/fall member 23 applied thereto,in the horizontal state of the fuel tank 100. In this case, a repulsionforce (“returning urge force” same as above) of the spring 17 increases,with increase of the compressed amount. Accordingly, the pressure thatallows the fuel to pass through the valve portion VE flowing in theinclined state of fuel tank 100 is set up by magnitude of the repulsionforce according to the compressed degree of the spring 17, and the firstpassage resistance set up based on the area size of the valve portionVE.

Here, the valve portion VE of the same structure as the above valveportion VA is composed of the part CF1 of the laterally outercircumference CF of the valve body 22 located between the point-contactpositions and does not make a point-contact, and a first communicationport which is a cut port of the first air passage 15. At thepoint-contact positions, the laterally outer circumference CF of thevalve body 22 is pressed onto the top portions of the plural convexportions 71T protruded into the inner surface 71E1 of the second sidewall 71E for point contacting. The first communication port is obtainedby cutting the inner surface 71E1 forming the first air passage and theboth convex portions 71T each adjacent to the inner surface 71E1, by thesurface obtained by outwardly extending the surface CS (for example, theconic surface) formed by connecting the center CO of the valve body 22and the laterally outer circumference CF.

Meanwhile, there may be valve portion that has a structure same as thevalve portion VB, instead of the valve portion VE in the embodiment (7).This the valve portion is composed of the part CF2 of the laterallyouter circumference CF of the valve body 22 between the line-contactpositions and does not make a line-contact, and a second communicationport that is a cut port of the second air passage. At the line-contactpositions, the laterally outer circumference CF of the valve body 22 ispressed onto the inner surface 71E of the second side wall 71E for linecontacting. The second communication port is obtained by cutting thesurface for forming concave portions to form the second air passage, bya plane obtained by outwardly extending the surface CS (for example, theconic surface) formed by connecting the center CO of the valve body 22and the laterally outer circumference CF.

Accordingly, in the inclined state of the fuel tank 100, the valve body22 and the rise/fall member 23 are pushed up by the repulsion force ofthe spring 17, and pressure of the flowing in fuel. As a result, thelaterally outer circumferences CF of an upper hemisphere of the valvebody 22 in the up/down direction, e.g. at ½ position are pressed ontothe top portions of the convex portions 71T of the second side wall 71Eof the inner cylinder valve body portion 71 for point contactingtherewith (or onto the inner surface 71E1 of the second side wall 71Efor line contacting therewith). Thus, the valve portion VE (or the valveportion of the same structure as the valve portion VB) is closed. Whenthe set-up pressure value is reached, the pressure of the flowed fuelopens the valve portion VE (or the valve portion of the same structureas the valve portion VB).

Hereinafter, an attaching order of the valve mechanism element 60 (referto FIG. 24 to FIG. 26) to the fuel tank 100 will be described. First,likewise the embodiment shown in FIG. 17, for example, the rise/fallmember 23 is accommodated with placing the valve body 22 thereon in thespace of the inner cylinder main body portion 71. Then, thesmall-diameter portion 23B of the rise/fall member 23 enters withplacing the valve body 22 thereon into the second space S32, and alsothe large-diameter portion 23A enters the first space S31.

Next, the spring 17 is accommodated in the space 23S of the rise/fallmember 23, the lower portion 51A of the first resistance member 51 isaccommodate in the large-diameter space 50S2 of the blow-up member 50,and the upper portion 51B is accommodated (arranged) in thesmall-diameter space 50S1, The large-diameter portion 50C of the blow-upmember 50 is abutted at the upper peripheral portion thereof to theundersurface of the step portion 16G, and the small-diameter portion 50Aof the blow-up member 50 is accommodated in the spring 17 accommodatedin the space 23S of the rise/fall member 23 for loose insertion.Accordingly, the first communication port 51E of the first resistancemember 51 is communicated with the small-diameter space 50S1 of theblow-up member 50 and the fuel tank 100.

Then, the cylinder main body 70 is attached to the attaching member 82.Here, for fixing the cylinder main body 70 to the attaching member 82 bythe bolt 80 and the nut 81, with accommodating the O-ring 86 in theaccommodation groove 74A, the attaching hole 74B of the attachingportion 74 and the attaching hole 82B of the attaching member 82 arecoincided. Then, the bolts 80 are inserted into the both holes, and thenuts 81 are screwed to the bolts for fixing. When the ultrasonicadhesion is used for fixing, with fitting the adhesion ribs 82A on theupper surface of the attaching member 82 into the accommodation groove74A, the ultrasonic adhesion is performed on the formed surface of theaccommodation groove 74A for fixing. The filter 79 is accommodated inthe large-diameter space 76S of the accommodation member 75, and theupper cap 88 is attached to the outer cylinder main body portion 72 ofthe cylinder main body 70 to cover an upper of the accommodation member75 and the upper part of the outer cylinder main body portion 72 fromabove. The screw 90 is inserted into the insertion holes 88C, 89A tomesh with the thread groove 72D formed in the swell portion 72C of theouter cylinder main body portion 72 along the concave portion 79A of thefilter 79. Thus, the upper cap 88 is attached to the outer cylinder mainbody portion 72 of the cylinder main body 70 for fixing.

The above-mentioned procedure completes assembling of the valvemechanism element 60. On attaching the valve mechanism element 60 thusconstituted to the fuel tank 100, the male screw of the attachingcylinder portion 100B formed on the outer surface of the fuel tank 100is meshed with the female screw 82D formed on the cylindrical portion82C of the attaching member 82.

In the embodiment where the urge force of the spring 17 is less than 1.0time(s) or less, for example 0.8 times or more to 0.93 times or less ofthe total weight of the rise/fall member 23 and the valve body 22, in agenerally horizontal state the fuel tank 100, the rise/fall member 23and the valve body 22 are lowered as shown in FIG. 25 with compressingthe spring 17 by the urge force less than the total weight thereof,regardless of the pressure value in the fuel tank 100.

Accordingly, the valve body 22 is not contacted with the convex portions71T on the inner surface 71E1 of the second side wall 71E (or with theinner surface 71E1 of the second side wall 71E) of the inner cylindermain body portion 71, thereby opening the valve portion VE (or the valveportion of the same structure as the valve portion VB). However, whenthe fuel tank 100 inclines, the weight of the rise/fall member 23 andthe valve body 22 applied to the spring 17 decreases according to thisinclined angle until it reaches 90 degrees. As a result, the spring 17compressed in the horizontal state of the fuel tank 100 increases in anexpansion length thereof, with increase of the inclined angle.Accordingly, with reduction of the weight applied to the spring 17, thespring 17 pushes up the valve body 22 by the urge force thereof. In thepredetermined length of the spring 17, the valve body 22 contacts withthe convex portions 71T on the inner surface 71E1 of the second sidewall 71E (or with the inner surface 71E1 of the second side wall 71E) ofthe inner cylinder main body portion 71. Accordingly, as shown in FIG.26, in the inclined state of the fuel tank 100, the fuel enters thespace 23S of the rise/fall member 23, through the space of the attachingcylinder portion 100B of the fuel tank 100, and through the space 82S1and the communication port 82S2 of the attaching member 82, the groove51D, the communication port 51E and the groove 51C of the firstresistance member 51, the small-diameter space 50S1 around the upperportion 51B. Here, the fuel pressure is reduced at the communicationport 51E of the first resistance member 51, and simultaneously, pressureof the fuel passing through the small-diameter space 50S1 around theupper portion 51B of the first resistance member 51 is reduced by theupper portion 51B. In this way, the fuel having increased in the flowvelocity thereof spouts into the space 23S of the rise/fall member 23.Accordingly, the spouted fuel pushes up the valve body 22 and therise/fall member 23 quickly together with the urge force of the spring17, thereby closing the valve portion VE (or the valve portion of thesame structure as the valve portion VB).

The pressure value 5 kPa that is a predetermined value to be describedlater in the embodiment of (7-1) is set based on the first passageresistance (or the second passage resistance) set based on the area sizeof the valve portion VE (or the valve portion of the same structure asthe valve portion VB), and magnitude of the urge force of the spring 17that is less than a total weight of the valve body 22 and the rise/fallmember 23.

As mentioned above, in the inclined state of the fuel tank 100, thevalve portion VE (or the valve portion of the same structure as thevalve portion VB) is kept closed until the inner pressure reaches thepredetermined value, for example 5 kPa. As a result, no fuel in thefirst space S31 of the inner cylinder main body portion 71 enters intothe large-diameter space 76S of the accommodation member 75 through theopening 71S of the upper horizontal wall 71F, Accordingly, no fuel isdischarged to the exterior of the fuel tank 100, i.e., exterior of thevalve mechanism element 60, thanks to the first passage resistance (orthe second passage resistance) set in the valve portion VE (or the valveportion of the same structure as the valve portion VB).

Accordingly, with suppressing discharge of the fuel to the exterior ofthe fuel tank 100, the valve mechanism portion of the valve mechanismelement 60 functions as the safety valve, which can improve the fuelconsumption and prevent the environmental contamination.

Also in the inclined fuel tank 100, when pressure of the fuel (liquidpressure) from the fuel tank 100 reaches for example 5 kPa, it lowersthe rise/fall member 23 and the valve body 22 against the urge force ofthe spring 17, thereby opening the valve portion VA (or the valveportion of the same structure as the valve portion VB). Thus, the fuelflow in, through the opening 71S of the inner cylinder main body portion71, the storage portion 71A of the inner cylinder main body portion 71,the small space 78S and the large-space 76S of the accommodation member75.

For this reason, the filter 79 in the large-diameter space 76S absorbs(takes in) the fuel in a space inside the filter 79. However, the fuelof amount larger than an absorbable amount flow to the exterior of thevalve mechanism element 60, through the opening 76A of the accommodationmember 75, the opening 72B and the removed portion 72A of the outercylinder main body portion 72 of the cylinder main body 70, and theconcave portion 88D of the upper cap 88.

When the fuel tank 100 returns to a horizontal state (including“generally horizontal state”), the valve body 22 and the rise/fallmember 23 fall by the weight thereof with compressing the spring 17,thereby opening the valve portion VE (or the valve portion of the samestructure as the valve portion VB), The fuel absorbed into the filter 79is guided to the storage portion 71A via a direct drip by its own weightor through the connection portion 77 having an upper surface inclinedinwardly. When the inner pressure of the fuel tank 100 changes to thenegative pressure with the fuel consumption by the engine 99, whilepermitting flow-in of the atmosphere through the concave portion 88D ofthe upper cap 88, the removed portion 72A and the opening 72B of theouter cylinder main body portion 72, and the opening 76A of theaccommodation member 75, the fuel absorbed into the filter 79 is guidedto the storage portion 71A, As mentioned above, the fuel stored in thestorage portion 71A is returned, by its own weight or due to fuelconsumption, to the fuel tank 100 together with the atmosphere, when thepressure in the fuel tank 100 changes to the negative pressure by thefuel consumption by the engine 99. In this way, the filter 79 isreproduced to the state before absorbing the fuel.

When the urge force of the spring 17 is selected less than 1.0 time(s)of the total weight of the rise/fall member 23 and the valve body 22,the valve mechanism element 60 operates as follow. In the generallyhorizontal state of the fuel tank 100, the fuel in the fuel tank 100 maygenerate an undulation by vibration, resulting in the increased fuelpressure. Even in this case, the fuel pressure reduced by thecommunication port 51E of the first resistance member 51, and thesmall-diameter space 50S1 of the blow-up member 50 that accommodates theupper part 51B of the first resistance member 51 thereon. Further, thefuel flowing out of the opening 71S upwardly is absorbed into the filter79, if any. In this way, flow-out of the fuel to the exterior of thevalve mechanism element 60 is suppressed. Even in the above-mentionedembodiment (6-2), the liquid is reduced in its liquid pressure by thefirst resistance member 51 or the second resistance member 52, whichsimilarly suppress the fuel flow-out to the exterior of the valvemechanism element 60.

(7-2) Embodiment of the Urge Force of the Spring 17 being 1.0 Time(s) orMore of the Total Weight of the Rise/Fall Member 23 and the Valve Body22 (Refer to FIG. 24 and FIG. 27)

In the following embodiment shown in FIG. 27, the upper surface of thespring 17 is 1.0 time(s) or more, for example 1.1 times or more to 2.0times or less of the total weight of the rise/fall member 23 and thevalve body 22, as described below,

First, in a generally horizontal state or the inclined state of the fueltank 100, during stoppage of the engine 99,

in spite of increase of the inner pressure in the fuel tank 100 resultedfrom the increased air temperature, as long as it is less than forexample 5 kPa, as mentioned above, the laterally outer circumference CFof the valve body 22 is point contacted with the top portions of theconvex portions 71T formed on the inner surface 71E1 of the second sidewall 71E of the inner cylinder main body portion 71 (or similarly thelaterally outer circumference CF is line contacted with the innersurface 71E1 of the second side wall 71E) by the urge force of thespring 17. Thus, the valve portion VE (or the valve portion of the samestructure as the valve portion VB) is closed. As a result, no VOC gas orno fuel in the first space S31 is discharged through the second spaceS32 and the opening 71S to the exterior of the fuel tank 100, i.e.,exterior of the valve mechanism element 60, thanks to the first passageresistance (or the second passage resistance) (refer to FIG. 27).

The pressure value 5 kPa that is a predetermined value to be describedlater in the embodiment (7-2) is set based on the first passageresistance (or the second passage resistance) set up based on the areasize of the valve portion VE (or the valve portion of the same structureas the valve portion VB), and magnitude of the urge force of the spring17 that is more than a total weight of the valve body 22 and therise/fall member 23.

Also in a generally horizontal state or the inclined state of the fueltank 100, during stoppage of the engine 99, with further temperaturerise of the external air, the VOC gas further increases in the generatedamount thereof, or the fuel expands in the fuel tank 100 filled with thefuel or the near to this state, which causes the further pressureincrease in the fuel tank 100. When the inner pressure reaches forexample 5 kPa, the VOC gas or the fuel from the fuel tank 100 rises inthe first air passage (or the second the air passage) formed on theinner surface 71E1 of the second side wall 71E of the inner cylindermain body portion 71, passing through the valve portion VE (or the valveportion of the same structure as the valve portion VB). This rising VOCgas or fuel lowers the valve body 22 and the rise/fall member 23downwardly against the urge force of the spring 17, thereby opening thevalve portion VE (or the valve portion of the same structure as thevalve portion VB). Accordingly, the VOC gas or the fuel flows in,through the opening 71S of the inner cylinder main body portion 71, tothe storage portion 71A of the inner cylinder main body portion 71, thesmall space 78S and the large space 76S of the accommodation member 75.

In this way, the VOC gas is discharged to the exterior of the valvemechanism element 60 through the filter 79 in the large-diameter space76S, and through the opening 76A of the accommodation member 75, theopening 72B and the removed portion 72A of the outer cylinder main bodyportion 72 of the cylinder main body 70, and the concave portion 88D ofthe upper cap 88. The fuel is absorbed in the inner space of the filter79 located in the large-diameter space 76S. Here, the fuel of amountlarger than an absorbable amount is discharged to the exterior of thevalve mechanism element 60, through the opening 76A of the accommodationmember 75, the opening 72B and the removed portion 72A of the outercylinder main body portion 72 of the cylinder main body 70, and theconcave portion 88D of the upper cap 88. That is, the excessive pressureof the fluid (the VOC gas and the fuel) from the fuel tank 100 isdischarged to the exterior of the valve mechanism element 60.

When the inner pressure of the fuel tank 100 reaches the pressure valueof less than 5 kPa resulted from discharge of the VOC gas or the fuel,the rise/fall member 23 and the valve body 22 are raised by the urgeforce of the spring 17. As a result, the laterally outer circumferenceCF of the valve body 22 point contacts with the plural convex portions71T (or similarly the laterally outer circumference CF line contactswith the inner surface 71E1 of the second side wall 71E), therebyclosing the valve portion VE (or the valve portion of the same structureas the valve portion VB). Thus, the valve mechanism portion functions asthe safety valve, which can improve the fuel consumption and prevent theenvironmental contamination.

In the closed state of the valve portion VE (or the valve portion of thesame structure as the valve portion VB), when the fuel tank 100 is ingenerally horizontal state, the fuel absorbed into the filter 79 isguided to storage portion 71A by the direct drip with its own gravity,or via the connection portion 77 having the upper surface inclinedinwardly. The inner pressure of the fuel tank 100 changes to thenegative pressure by consumption of the fuel for driving the engine 99.Here, while permitting the atmosphere to flow in the fuel tank 100through the concave portion 88D of the upper cap 88, the removed portion72A and the opening 72B of the outer cylinder main body portion 72, andthe opening 76A of the accommodation member 75, the fuel absorbed intothe filter 79 is guided to the storage portion 71A. As mentioned above,when the fuel consumption for driving the engine 99 changes the pressurein the fuel tank 100 to the negative pressure, the fuel stored in thestorage portion 71A by its own gravity or with its consumption returnsto the fuel tank 100 together with the atmosphere. In this way, thefilter 79 is reproduced to the state before absorbing the fuel.

Meanwhile, the valve mechanism element 60 of the embodiments (7-1) and(7-2) can also be used as the above-mentioned filler cap 10

(8) Others

In all the above-mentioned embodiments, the attaching method ormechanism of the filler cap 10 or the valve mechanism element 60 to thefuel tank 100 have been explained by employing the screw or the spring33. However, the screw or the spring 33 does not limit the attachingmethod or mechanism. The valve-mechanism element 60 may be attached tothe fuel tank 100 directly, or attached indirectly via a connectionmember such as a hose, without requiring any specific attaching methodor the structure.

In all the embodiments mentioned above, the valve portion VA, VB, VCand/or VE is the narrowest opening among the possible openings that areformed between the laterally outer circumference of the valve body 22 orthe valve body portion 22A, and the inner surface 16E1 of the cylindermain body 16 (including the convex portions or the concave portions) orthe inner surface 71E1 of the inner cylinder main body portion 71(including the convex portions or the concave portions).

That is, in all the embodiments mentioned above, the valve portion VA,VB and/or VE is composed of

(a) the part of the laterally outer circumference CF of the valve body22 (or the part of the laterally outer circumference CP of thehemisphere portion 22A1 of the valve body portion 22A) located betweenthe point-contact positions on the rise/fall member 23 where thelaterally outer circumference CF of the valve body 22 (or the laterallyouter circumference CP of the hemisphere portion 22A1) is pressed ontothe plural convex portions 16T, 71T, that does not make a point-contact,or

(b) the part of the laterally outer circumference CF of the valve body22 (or the part of the laterally outer circumference CP of thehemisphere portion 22A1) located between line-contact positions on therise/fall member 23 where the laterally outer circumference CF of thevalve body 22 (or the laterally outer circumference CP of the hemisphereportion 22A1) is pressed onto the inner surface 16E1, 71E1 of the secondside wall 16E, 71E, that does not make the line-contact, and

(c) the first communication port which is the cut port of the first airpassage obtained by cutting the inner surface 16E1, 71E1 and the bothconvex portions 16T, 71T each adjacent to the inner surface 16E1, 71E1forming the first air passage, so that among openings formed between thepart of the laterally outer circumference CF not point contacting (thepart of the laterally outer circumference CP not point contacting) andthe inner surface 16E1, 71E1 and both adjacent convex portions, thenarrowest opening is formed, or

(d) the second communication port which is the cut port of the secondair passage by cutting a plane for forming concave portions to form thesecond air passage, so that among openings formed between the part ofthe laterally outer circumference CF not line contacting (the part ofthe laterally outer circumference CP not line contacting) and the innersurface 16E1, 71E1, the narrowest opening is formed.

Meanwhile, in all the embodiments explained above, the fuel tank 100 maybe subjected to a heat insulation processing to suppress increase of theinner pressure. The filler cap 10 or the valve mechanism element 60further suppress, when combined with such fuel tank, the discharge ofthe VOC gas or the fuel to the exterior of the fuel tank 100, leading toimprovement of the fuel consumption and prevention of the environmentalcontamination. Such suppressed discharge may also meet with of examiningmethod in California, U.S.A.

According to the above-mentioned present invention, the filler cap orthe valve mechanism element 60 for the fuel tank can be provided, thatcan further prevent the environmental pollution and can improve the fuelconsumption, compared with the technology shown in the above-mentionedpatent documents 1 and 2, without discharging the fuel or the harmfulVOC gas evaporated therefrom externally.

Hereinbefore, the embodiments of the present invention have beenexplained, but a person skilled in the art may conceive variousalternation, corrections or modification based on the above-mentionedexplanation. The present invention contains above-mentioned variousalternative examples, corrected examples, or modified examples withoutdeviating from the scope of the present invention.

EXPLANATION OF REFERENCE

-   10 filler cap-   12 outer cap-   13 inner cap-   15 first air passage-   15 a second air passage-   16 cylinder main body-   16E1 inner surface-   16T convex portion-   17 spring-   22 valve body-   23 rise/fall member-   23A large-diameter portion-   23B small-diameter portion-   23 s space-   24, 25 air passage-   50 blow-up member-   50S1 small-diameter space-   50S2 large-diameter space-   51 first resistance member-   51E communication port-   52 second resistance member-   52 c communication port-   60 valve mechanism element 60-   61 filler cap-   70 cylinder main body-   71 inner cylinder main body portion-   71A storage portion-   71E second side wall-   71S opening-   72 outer cylinder main body portion-   73 connection portion-   74 attaching portion-   75 accommodation member-   79 filter-   82 attaching member-   98 fill opening-   100 fuel tank-   S1 first space-   S2 second space-   S3 opening-   VA, VB, VE valve portion-   RA first communication port-   RB second communication port

What is claimed is:
 1. A filler cap for a fuel tank attached to the fueltank, the filler cap comprising a cap main body including an outer capand an inner cap, the filler cap having an air passage for communicatingan interior and an exterior of the fuel tank, and a valve mechanismportion disposed in the air passage, the valve mechanism portioncomprising: a cylinder main body generally centrally disposed inside theinner cap, the cylinder main body formed with a cylindrical first spacecommunicated with the interior of the fuel tank, a second space oftruncated cone shape communicated with the first space from above, andan opening communicated with the second space from above andcommunicated with the interior of the fuel tank at an upper surface, thecylinder main body formed with, on an inner surface that forms thesecond space, plural convex portions elongate in an up/down directionand protruding inwardly with keeping an interval to form a first airpassage between respective convex portions, or on the inner surface,plural concave portions elongate in the up/down direction with keepingan interval to form a second air passage; a rise/fall member of endclosed hollow cylindrical shape having an upper surface and opened at alower surface, the rise/fall member having a large-diameter portion atlower part and being accommodated in the first space, and asmall-diameter portion of truncated cone shape in an outer profile at anupper part and accommodated in the second space; a spherical valve bodyplaced on an upper surface of the small-diameter portion of therise/fall member, a laterally outer circumference of the valve bodypoint contacting with the plural convex portions protruded to the innersurface of the cylinder main body that forms the second space, or thelaterally outer circumference line contacting with the inner surface ofthe cylinder main body that forms the second space; and an urge memberdisposed in a space of the large-diameter portion of the rise/fallmember, the urge member pushing up the rise/fall member so that thelaterally outer circumference of the valve body placed on thesmall-diameter portion is pressed onto the plural convex portions forurging a point-contact therewith, or pushing up the rise/fall member sothat the laterally outer circumference of the valve body placed on thesmall-diameter portion is pressed onto the inner surface of the cylindermain body for urging a line-contact therewith, wherein a valve portionis comprised of (a) a part of the laterally outer circumference of thevalve body on the rise/fall member located between the point-contactpositions, where the laterally outer circumference of the valve body ispressed onto the plural convex portions, that is not point contacted, or(b) a part of the laterally outer circumference of the valve bodylocated between line-contact positions on the rise/fall member, wherethe laterally outer circumference of the valve body is pressed onto theinner surface, that is not line contacted, and (c) a first communicationport that is a cut port of the first air passage obtained by cutting theinner surface and the both convex portions respectively adjacent to theinner surface forming the first air passage, by a surface obtained byoutwardly extending a surface formed by connecting a center of the valvebody and the laterally outer circumference, or (d) a secondcommunication port that is a cut port of the second air passage obtainedby cutting a plane for forming concave portions to form the second airpassage, by a surface obtained by outwardly extending a surface formedby connecting a center of the valve body and the laterally outercircumference, in a state where the laterally outer circumference of thevalve body on the rise/fall member is pressed onto the convex portionsfor point contacting therewith, or in a state where the laterally outercircumference of the valve body on the rise/fall member is pressed ontothe inner surface of the cylinder main body for line contactingtherewith, with increase of a pressure in the fuel tank due to anevaporated gas resulted from a vaporized fuel in the fuel tank, when thepressure in the fuel tank reaches a predetermined pressure value setbased on a first passage resistance or a second passage resistance setup based on an area size of the valve portion constituted of the part ofthe laterally outer circumference not point contacted or the part of thelaterally outer circumference not line contacted and the firstcommunication port or the second communication port, and a magnitude ofan urge force of the urge member that is more than a total weight of thevalve body and the rise/fall member, the evaporated gas rises in thefirst air passage against the first passage resistance, or in the secondair passage against the second passage resistance, passing through thevalve portion, and the rising evaporated gas lowers the valve body andthe rise/fall member downwardly against the urge force of the urgemember, and opens the valve portion to discharge an excessively largepressure in the fuel tank to the exterior of the fuel tank through thefirst space, the second space and the opening.
 2. A filler cap for afuel tank attached to the fuel tank, the filler cap comprising a capmain body including an outer cap and an inner cap, the filler cap havingan air passage for communicating an interior and an exterior of the fueltank, and a valve mechanism portion disposed in the air passage, thevalve mechanism portion comprising: a cylinder main body generallycentrally disposed inside the inner cap, the cylinder main body formedwith a cylindrical first space communicated with the interior of thefuel tank, a second space of truncated cone shape communicated with thefirst space from above, and an opening communicated with the secondspace from above and communicated with the interior of the fuel tank atan upper surface, the cylinder main body formed with, on an first innersurface that forms the second space, plural convex portions elongate inan up/down direction and protruding inwardly with keeping an interval toform a first air passage between respective convex portions, or on thefirst inner surface, plural concave portions elongate in the up/downdirection with keeping an interval to form a second air passage; arise/fall member of end closed hollow cylindrical shape having an uppersurface and opened at a lower surface to form a space inside, therise/fall member having a large-diameter portion at lower part and beingaccommodated in the first space, and a small-diameter portion oftruncated cone shape in an outer profile at an upper part andaccommodated in the second space; a spherical valve body placed on anupper surface of the small-diameter portion of the rise/fall member, alaterally outer circumference of the valve body point contacting withthe plural convex portions protruded to the first inner surface of thecylinder main body that forms the second space, or the laterally outercircumference line contacting with the first inner surface of thecylinder main body that forms the second space; a coil spring disposedin the space of the rise/fall member, the coil spring pushing up therise/fall member so that the laterally outer circumference of the valvebody placed on the small-diameter portion is pressed onto the pluralconvex portions for urging a point-contact therewith, or pushing up therise/fall member so that the laterally outer circumference of the valvebody placed on the small-diameter portion is pressed onto the firstinner surface of the cylinder main body for urging a line-contacttherewith, a blow-up member of hollow cylindrical shape including asmall-diameter portion loosely inserted into the coil springaccommodated in the space of the rise/fall member and formed asmall-diameter space, a step portion having a diameter larger than thatof the small-diameter portion and supporting a lower portion of the coilspring on an upper surface, and a large-diameter portion having adiameter larger than that of the step portion and formed with alarge-diameter space communicated with the small diameter space; aresistance member for reducing the pressure of an evaporated gas or afuel from the fuel tank, the resistance member including a lower portionof circular shape in a planar view having a communication portcommunicated with the large-diameter space of the blow-up member and thefuel tank, and a cylindrical upper portion centrally studded on an uppersurface of the lower portion, the lower portion being accommodated inthe large-diameter space of the blow-up member to the undersurface ofthe step portion with abutting an upper surface peripheral portion ofthe lower portion, and the upper portion being accommodated in thesmall-diameter space with separated from a second inner surface definingthe small-diameter space, wherein a valve portion is comprised of (a) apart of the laterally outer circumference of the valve body on therise/fall member located between the point-contact positions, where thelaterally outer circumference of the valve body is pressed onto theplural convex portions, that is not point contacted, or (b) a part ofthe laterally outer circumference of the valve body located betweenline-contact positions on the rise/fall member, where the laterallyouter circumference of the valve body is pressed onto the first innersurface, that is not line contacted, and (c) a first communication portthat is a cut port of the first air passage obtained by cutting thefirst inner surface and the both convex portions respectively adjacentto the first inner surface forming the first air passage, by a surfaceobtained by outwardly extending a surface formed by connecting a centerof the valve body and the laterally outer circumference, or (d) a secondcommunication port that is a cut port of the second air passage obtainedby cutting a plane for forming concave portions to form the second airpassage, by a surface obtained by outwardly extending a surface formedby connecting a center of the valve body and the laterally outercircumference, and in a state where the laterally outer circumference ofthe valve body on the rise/fall member is pressed onto the convexportions for point contacting therewith, or in a state where thelaterally outer circumference of the valve body on the rise/fall memberis pressed onto the first inner surface of the cylinder main body forline contacting therewith, with increase of a pressure in the fuel tankdue to the evaporated gas resulted from a vaporized fuel or an expansionof the fuel in the fuel tank, when the pressure in the fuel tank reachesa predetermined pressure value set based on a first passage resistanceor a second passage resistance set up based on an area size of the valveportion constituted of the part of the laterally outer circumference notpoint contacted or the part of the laterally outer circumference notline contacted and the first communication port or the secondcommunication port, and a magnitude of an urge force of the coil springthat is more than a total weight of the valve body and the rise/fallmember, the evaporated gas or the expanded fuel rises through thecommunication port of the resistance member, the small-diameter space ofthe blow-up member, a gap between a lower end of the rise/fall memberand the large-diameter portion of the blow-up member, a gap between therise/fall member and the cylinder main body, in the first air passageagainst the first passage resistance or in the second air passageagainst the second passage resistance, passing through the valveportion, and the rising evaporated gas or the rising expanded fuellowers the valve body and the rise/fall member downwardly against theurge force of the coil spring, and opens the valve portion to dischargean excessively large pressure in the fuel tank to the exterior of thefuel tank through the first space, the second space and the opening. 3.A filler cap for a fuel tank attached to the fuel tank, the filler capcomprising a cap main body including an outer cap and an inner cap, thefiller cap having an air passage for communicating an interior and anexterior of the fuel tank, and a valve mechanism portion disposed in theair passage, the valve mechanism portion comprising: a cylinder mainbody generally centrally disposed inside the inner cap, the cylindermain body formed with a cylindrical first space communicated with theinterior of the fuel tank, a second space of truncated cone shapecommunicated with the first space from above, and an openingcommunicated with the second space from above and communicated with theinterior of the fuel tank at an upper surface, the cylinder main bodyformed with, on an inner surface that forms the second space, pluralconvex portions elongate in an up/down direction and protruding inwardlywith keeping an interval to form a first air passage between respectiveconvex portions, or on the inner surface plural, concave portionselongate in the up/down direction with keeping an interval to form asecond air passage; a rise/fall member of end closed hollow cylindricalshape having an upper surface and opened at a lower surface to form aspace inside, the rise/fall member having a large-diameter portion atlower part and being accommodated in the first space, and asmall-diameter portion of truncated cone shape in an outer profile at anupper part and accommodated in the second space; a spherical valve bodyplaced on an upper surface of the small-diameter portion of therise/fall member in a state a laterally outer circumference capable ofpoint contacting with the plural convex portions protruded to the innersurface of the cylinder main body that forms the second space, or in astate the laterally outer circumference of the valve body capable ofline contacting with the inner surface of the cylinder main body thatforms the second space; a coil spring disposed in the space of therise/fall member for pushing up the rise/fall member to allow thelaterally outer circumference of the valve body placed on thesmall-diameter portion to be pressed onto the plural convex portions forpoint contacting therewith, or for pushing up the rise/fall member toallow the laterally outer circumference of the valve body placed on thesmall-diameter portion to be pressed onto the inner surface of thecylinder main body for line contacting therewith; a blow-up member ofhollow cylindrical shape including a small-diameter portion looselyinserted into the coil spring accommodated in the space of the rise/fallmember and formed a small-diameter apace, a step portion having adiameter larger than that of the small-diameter portion and supporting alower portion of the coil spring on an upper surface, and alarge-diameter portion having a diameter larger than that of the stepportion, being formed with a large-diameter space communicated with thesmall-diameter space, and being accommodated in a space funned in abottom wall of the inner cap; and a resistance member of circular shapein a planar view having a communication port communicated with thelarge-diameter space of the blow-up member and the fuel tank, theresistance member being accommodated in the space formed in the bottomwall of the inner cap with abutting to an undersurface of thelarge-diameter portion of the blow-up member; wherein a valve portion iscomprised of (a) a part of the laterally outer circumference of thevalve body on the rise/fall member located between the point-contactpositions, where the laterally outer circumference of the valve body ispressed onto the plural convex portions, that is not point contacted, or(b) a part of the laterally outer circumference of the valve bodylocated between line-contact positions on the rise/fall member, wherethe laterally outer circumference of the valve body is pressed onto theinner surface, that is not line contacted, and (c) a first communicationport that is a cut port of the first air passage obtained by cutting theinner surface and the both convex portions respectively adjacent to theinner surface forming the first air passage, by a surface obtained byoutwardly extending a surface formed by connecting a center of the valvebody and the laterally outer circumference, or (d) a secondcommunication port that is a cut port of the second air passage obtainedby cutting a plane for forming concave portions to form the second airpassage, by a surface obtained by outwardly extending a surface formedby connecting a center of the valve body and the laterally outercircumference, and in a state where the rise/fall member and the valvebody are lowered by the urge force that is less than a total weight ofthe valve body and the rise/fall member with compressing the coilspring, and the laterally outer circumference of the valve body on therise/fall member is not point contacted with the plural convex portions,or the laterally outer circumference of the valve body on the rise/fallmember is not line contacted with the inner surface of the cylinder mainbody thereby opening the valve portion, in an inclined state of the fueltank, a weight of the rise/fall member and the valve body applied to thecoil spring decreases according to the inclined angle, when the coilspring expands its length to have a predetermined length, the valve bodycontacts with the convex portions on the inner surface or contacts withthe inner surface of the cylinder main body, and the fuel spouts, aftera pressure reduction at the communication port of the resistance member,into the space of the rise/fall member from the small-diameter space ofthe blow-up member, so that the spouted fuel pushes up the valve bodyand the rise/fall member thereby closing the valve portion together withthe urge force of the coil spring.
 4. A valve body device for a fueltank, comprising a filler cap and a valve mechanism element, the fillercap opening/closing a fill opening provided on an upper surface of thefuel tank storing a fuel to be supplied to an engine, and interruptingcommunication of the fuel tank and an atmosphere through the fillopening in a closure of the fill opening, the valve mechanism elementincluding: a cylinder main body composed of a cylindrical outer cylindermain body portion, an inner cylinder main body portion being generallycentrally connected to a lower part of the outer cylinder main bodyportion via a connection portion and being formed with a storage portionin an upper part thereof, and an attaching portion having a step steppedbelow relative to the connection portion at a lower end part of theouter cylinder main body portion and extending outwardly, the innercylinder main body portion being formed with a first cylindrical space,a second space of truncated cone shape communicated with the first spacefrom above, a third space being formed by cutting and removing an innerend part of the connection portion and a lower end part of the innercylinder main body portion and communicated with the first space frombelow, a fourth space formed by stepping the connecting portion and theattaching portion and connected to the third space from below, and anopening for communicating the second space with the exterior of the fueltank, the cylinder main body being formed with, on a first inner surfacethat forms the second space, plural convex portions elongate in anup/down direction and protruding inwardly with keeping an interval toform a first air passage between respective convex portions, or, on thefirst inner surface, plural concave portions elongate in the up/downdirection with keeping an interval to form a second air passage; arise/fall member of end closed hollow cylindrical shape having an uppersurface and opened at a lower surface to form a space inside, therise/fall member having a large-diameter portion at lower part and beingaccommodated in the first space, and a small-diameter portion oftruncated cone shape in an outer profile at an upper part andaccommodated in the second space; a spherical valve body placed on anupper surface of the small-diameter portion of the rise/fall member, ina state a laterally outer circumference of the valve body capable ofpoint contacting with the plural convex portions protruded to the firstinner surface of the cylinder main body that forms the second space, orin a state the laterally outer circumference capable of line contactingwith the first inner surface of the cylinder main body that forms thesecond space; a coil spring disposed in the space of the rise/fallmember for pushing up the rise/fall member to allow the laterally outercircumference of the valve body placed on the small-diameter portion tobe pressed onto the plural convex portions for point contactingtherewith, or for pushing up the rise/fall member to allow the laterallyouter circumference of the valve body placed on the small-diameterportion to be pressed onto the inner surface of the cylinder main bodyfor line contacting therewith; a blow-up member of hollow cylindricalshape including a small-diameter portion loosely inserted into the coilspring accommodated in the space of the rise/fall member and formed asmall-diameter apace, a step portion having a diameter larger than thatof the small-diameter portion and supporting a lower portion of the coilspring on an upper surface, and a large-diameter portion having adiameter larger than that of the step portion and formed with alarge-diameter space communicated with the small-diameter space andaccommodated in the fourth space formed in the cylinder main body; aresistance member composed of a lower portion of circular shape in aplanar view having a communication port communicated with thesmall-diameter space of the blow-up member and the fuel tank, and acylindrical upper portion centrally studded on an upper surface of thelower portion, the lower portion being accommodated in thelarge-diameter space of the blow-up member to the undersurface of thestep portion with abutting an upper surface peripheral portion of thelower portion, and the upper portion being accommodated in thesmall-diameter space with separated from a second inner surface definingthe small-diameter space; an attaching member attached to anundersurface of the attaching portion of the cylinder main body, andbeing formed with a communication path communicated with an openingdefined in the fuel tank to be attached to the fuel tank directly orindirectly, in a state where the blow-up member that accommodates thelower portion of the resistance member in the large-diameter spacethereof and that is disposed with the upper portion in thesmall-diameter space thereof, is loosely inserted in the coil springdisposed in the space of the rise/fall member, and the rise/fall memberis accommodated in the first space and the second space of the cylindermain body that places the valve body on an upper surface thereof; anaccommodation member of hollow cylindrical shape accommodating a porousfilter with a space that collects a foreign matter thereof forpreventing entry into the fuel tank, and being attached to the innercylinder main body portion of the cylinder main body; and an upper capattached to the outer cylinder main body portion from above so that aspace in the accommodation member and a space in the outer cylinder mainbody portion are communicated with an atmosphere; wherein a valveportion is comprised of (a) a part of the laterally outer circumferenceof the valve body on the rise/fall member located between thepoint-contact positions, where the laterally outer circumference of thevalve body is pressed onto the plural convex portions, that is not pointcontacted, or (b) a part of the laterally outer circumference of thevalve body located between line-contact positions on the rise/fallmember, where the laterally outer circumference of the valve body ispressed onto the first inner surface, that is not line contacted, and(c) a first communication port that is a cut port of the first airpassage obtained by cutting the first inner surface and the both convexportions respectively adjacent to the first inner surface forming thefirst air passage, by a surface obtained by outwardly extending asurface formed by connecting a center of the valve body and thelaterally outer circumference, or (d) a second communication port thatis a cut port of the second air passage obtained by cutting a plane forforming concave portions to form the second air passage, by a surfaceobtained by outwardly extending a surface formed by connecting a centerof the valve body and the laterally outer circumference, and in a statewhere the rise/fall member and the valve body are lowered by the urgeforce that is less than a total weight of the valve body and therise/fall member with compressing the coil spring, and the laterallyouter circumference of the valve body on the rise/fall member is notpoint contacted with the plural convex portions, or the laterally outercircumference of the valve body on the rise/fall member is not linecontacted with the first inner surface of the cylinder main body therebyopening the valve portion, in an inclined state of the fuel tank, aweight of the rise/fall member and the valve body applied to the coilspring decreases according to the inclined angle, when the coil springexpands its length to have a predetermined length, the valve bodycontacts with the convex portions on the first inner surface or contactswith the first inner surface of the cylinder main body, and the fuelfrom the fuel tank through the communication path of the attachingmember is reduced the pressure at the communication port of theresistance member and the small-diameter space of the blow-up memberthat accommodates the upper portion of the resistance member, and thenthe fuel spouts into the space of the rise/fall member from thesmall-diameter space of the blow-up member, so that the spouted fuelpushes up the valve body and the rise/fall member thereby closing thevalve portion together with the urge force of the coil spring, and whenthe pressure of the fuel from the fuel tank reaches a predeterminedpressure value, the rise/fall member and the valve body are loweredthereby opening the valve portion, the fuel from the fuel tank flows inthe space of the accommodation member from the first space and thesecond space of the cylinder main body through the opening, the flow-infuel is absorbed in the space inside the filter, in a returnedhorizontal state of the fuel tank, during the pressure in the fuel tankchanging to a negative pressure due to consumption for driving theengine, the fuel absorbed in the filter is stored in the store portionand is returned to the fuel tank.
 5. A valve body device for a fueltank, comprising a filler cap and a valve mechanism element, the fillercap opening/closing a fill opening provided on an upper surface of thefuel tank storing a fuel to be supplied to an engine, and interruptingcommunication of the fuel tank and an atmosphere through the fillopening in a closure of the fill opening, the valve mechanism elementincluding: a cylinder main body composed of a cylindrical outer cylindermain body portion, an inner cylinder main body portion being generallycentrally connected to a lower part of the outer cylinder main bodyportion via a connection portion and being formed with a storage portionin an upper part thereof, and an attaching portion having a step steppedbelow relative to the connection portion at a lower end part of theouter cylinder main body portion and extending outwardly, the innercylinder main body portion being formed with a first cylindrical space,a second space of truncated cone shape communicated with the first spacefrom above, a third space being formed by cutting and removing an innerend part of the connection portion and a lower end part of the innercylinder main body portion and communicated with the first space frombelow, a fourth space formed by stepping the connecting portion and theattaching portion and connected to the third space from below, and anopening for communicating the second space with the exterior of the fueltank, the cylinder main body being formed with, on a first inner surfacethat forms the second space, plural convex portions elongate in anup/down direction and protruding inwardly with keeping an interval toform a first air passage between respective convex portions, or, on thefirst inner surface, plural concave portions elongate in the up/downdirection with keeping an interval to form a second air passage; arise/fall member of end closed hollow cylindrical shape having an uppersurface and opened at a lower surface to form a space inside, therise/fall member having a large-diameter portion at lower part and beingaccommodated in the first space, and a small-diameter portion oftruncated cone shape in an outer profile at an upper part andaccommodated in the second space; a spherical valve body placed on anupper surface of the small-diameter portion of the rise/fall member, alaterally outer circumference of the valve body point contacting withthe plural convex portions protruded to the first inner surface of thecylinder main body that forms the second space, or the laterally outercircumference of the valve body line contacting with the first innersurface of the cylinder main body that forms the second space; a coilspring disposed in the space of the rise/fall member, the coil springpushing up the rise/fall member so that the laterally outercircumference of the valve body placed on the small-diameter portion ispressed onto the plural convex portions for urging a point-contacttherewith, or pushing up the rise/fall member so that the laterallyouter circumference of the valve body placed on the small-diameterportion is pressed onto the first inner surface of the cylinder mainbody for urging a line-contact therewith, a blow-up member of hollowcylindrical shape composed of a small-diameter portion loosely insertedinto the coil spring accommodated in the space of the rise/fall memberand formed a small-diameter space, a step portion having a diameterlarger than that of the small-diameter portion and supporting a lowerportion of the coil spring on an upper surface, and a large-diameterportion having a diameter larger than that of the step portion andformed with a large-diameter space communicated with the small-diameterspace and accommodated in the fourth space formed in the cylinder mainbody; a resistance member composed of a lower portion of circular shapein a planar view having a communication port communicated with thesmall-diameter space of the blow-up member and the fuel tank, and acylindrical upper portion centrally studded on an upper surface of thelower portion, the lower portion being accommodated in thelarge-diameter space of the blow-up member to the undersurface of thestep portion with abutting an upper surface peripheral portion of thelower portion, and the upper portion being accommodated in thesmall-diameter space with separated from a second inner surface definingthe small-diameter space; an attaching member attached to anundersurface of the attaching portion of the cylinder main body, andbeing formed with a communication path communicated with an openingdefined in the fuel tank to be attached to the fuel tank directly orindirectly, in a state where the blow-up member that accommodates thelower portion of the resistance member in the large-diameter spacethereof and that is disposed with the upper portion in thesmall-diameter space thereof, is loosely inserted in the coil springdisposed in the space of the rise/fall member, and the rise/fall memberis accommodated in the first space and the second space of the cylindermain body that places the valve body on an upper surface thereof; anaccommodation member of hollow cylindrical shape accommodating a porousfilter with a space that collects a foreign matter thereof forpreventing entry into the fuel tank, and being attached to the innercylinder main body portion of the cylinder main body; and an upper capattached to the outer cylinder main body portion from above so that aspace in the accommodation member and a space in the outer cylinder mainbody portion are communicated with an atmosphere; wherein a valveportion is comprised of (a) a part of the laterally outer circumferenceof the valve body on the rise/fall member located between thepoint-contact positions, where the laterally outer circumference of thevalve body is pressed onto the plural convex portions, that is not pointcontacted, or (b) a part of the laterally outer circumference of thevalve body located between line-contact positions on the rise/fallmember, where the laterally outer circumference of the valve body ispressed onto the first inner surface, that is not line contacted, and(c) a first communication port that is a cut port of the first airpassage obtained by cutting the first inner surface and the both convexportions respectively adjacent to the first inner surface forming thefirst air passage, by a surface obtained by outwardly extending asurface formed by connecting a center of the valve body and thelaterally outer circumference, or (d) a second communication port thatis a cut port of the second air passage obtained by cutting a plane forforming concave portions to form the second air passage, by a surfaceobtained by outwardly extending a surface formed by connecting a centerof the valve body and the laterally outer circumference, and in a statewhere the laterally outer circumference of the valve body on therise/fall member is pressed onto the convex portions for pointcontacting therewith, or in a state where the laterally outercircumference of the valve body on the rise/fall member is pressed ontothe first inner surface of the cylinder main body for line contactingtherewith, with increase of a pressure in the fuel tank due to anevaporated gas resulted from a vaporized fuel in the fuel tank or due toan expanded fuel, when the pressure in the fuel tank reaches apredetermined pressure value set based on a first passage resistance ora second passage resistance set up based on an area size of the valveportion constituted of the part of the laterally outer circumference notpoint contacted or the part of the laterally outer circumference notline contacted and the first communication port or the secondcommunication port, and a magnitude of an urge force of the coil springthat is more than a total weight of the valve body and the rise/fallmember, the evaporated gas or the expanded fuel rises via thecommunication port of the resistance member, the small-diameter space ofthe blow-up member, a gap between a lower end of the rise/fall memberand the larger-diameter portion of the blow-up member, and a gap betweenthe rise/fall member and the cylinder main body, in the first airpassage against the first passage resistance or in the second airpassage against the second passage resistance, passing through the valveportion, and the rising evaporated gas or the rising evaporated fuellowers the valve body and the rise/fall member downwardly against theurge force of the coil spring, and opens the valve portion to dischargean excessively large pressure in the fuel tank to the exterior of thefuel tank through the first space, the second space and the opening forabsorbing the fuel in the filter.